From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33BAAC433EF for ; Tue, 29 Mar 2022 12:40:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236401AbiC2Mm2 (ORCPT ); Tue, 29 Mar 2022 08:42:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236376AbiC2MmP (ORCPT ); Tue, 29 Mar 2022 08:42:15 -0400 Received: from mail-ed1-x54a.google.com (mail-ed1-x54a.google.com [IPv6:2a00:1450:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E9662013F2 for ; Tue, 29 Mar 2022 05:40:32 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id v15-20020a50f08f000000b0041902200ab4so10938751edl.22 for ; Tue, 29 Mar 2022 05:40:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=3CQYkeXdj1XVJNClFGQhidAhDBObT15U+enV+/AhM6A=; b=Rs1GnbfzAh48GyKvXrTviY6xmcPrSlCBrhBam52FN5lKhGkSSoDXuC/+sTSLnCX5XO /i4ncOwVT391qnv8EZbsDSgMBgczL/nCzy9Jqzu/nf38q/o+9kZr7KSlVoUWiViJ9870 M0b0YE9E38a6zKyq5m0p8rIATZFa84ILdXxkvPpuNk7AfC4/9N8vExikGAHybh4Pb0rX 8KcC4OmYsI0xN2dW728NWEU8I1Adn92Xl7Ph9hUyWVnxsPmYOh4rsrvl7JDTJxDDCuk+ Va2vfsVuAq80Q0B5XplgXmEPTnrJ0hx+BQmCkMVH18sZhimHpdOgC1BUg2+kBBmprNgo nutA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=3CQYkeXdj1XVJNClFGQhidAhDBObT15U+enV+/AhM6A=; b=PiHPj49wTnzCJT8B6hf91x4L1jrGSaNe10CZCuqcpVaY50BcsfYHTOfxP0FGI/5HRO e3q1dQhkdyDlEF9PxVU4RH/ncJ3ph4eO4V0edwqB389oyh4Z+QhaQi+iQGhA2/UM3juX i5lmFjfGRWuUpnoIJFxsORb4Ug5vGlUihpA0DiOnLnCsQ83+gowEGZahIF/Ph5Dch0uC D1q6F4to6twtdXK5CuhiqYVszkPG9ZRpQZdH+b4MspVjFQkZxXPWiOXgIOUWGnzMMFzq BKi3uk9oz4z94EdrKfvAKXzKrezblBCsc5XPf1jQkzvVC5tqa8MC/MXfWKJ2xj+Qey1Z MlXw== X-Gm-Message-State: AOAM531VIoSxIpxC98jDFJjPz+JRiymlQrDeCULFRKzfjaradk5eB3ER X18s3TIGs/W2K6W4tS9yblZ2Z6m1RGM= X-Google-Smtp-Source: ABdhPJwxfLc7E5CGNpFchMAnZqVrfibLaBjl6ZrGzY59hWiYTgmr/LPloRQjIFWbW4/icF3FYORBAEJgcTc= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:9c82:b0:6df:c5f0:d456 with SMTP id fj2-20020a1709069c8200b006dfc5f0d456mr34088614ejc.287.1648557630566; Tue, 29 Mar 2022 05:40:30 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:30 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-2-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 01/48] x86: add missing include to sparsemem.h From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Dmitry Vyukov sparsemem.h:34:32: error: unknown type name 'phys_addr_t' extern int phys_to_target_node(phys_addr_t start); ^ sparsemem.h:36:39: error: unknown type name 'u64' extern int memory_add_physaddr_to_nid(u64 start); ^ Signed-off-by: Dmitry Vyukov Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Ifae221ce85d870d8f8d17173bd4= 4d5cf9be2950f --- arch/x86/include/asm/sparsemem.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/include/asm/sparsemem.h b/arch/x86/include/asm/sparse= mem.h index 6a9ccc1b2be5d..64df897c0ee30 100644 --- a/arch/x86/include/asm/sparsemem.h +++ b/arch/x86/include/asm/sparsemem.h @@ -2,6 +2,8 @@ #ifndef _ASM_X86_SPARSEMEM_H #define _ASM_X86_SPARSEMEM_H =20 +#include + #ifdef CONFIG_SPARSEMEM /* * generic non-linear memory support: --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39C0AC433F5 for ; Tue, 29 Mar 2022 12:40:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236423AbiC2Mme (ORCPT ); Tue, 29 Mar 2022 08:42:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236381AbiC2MmU (ORCPT ); Tue, 29 Mar 2022 08:42:20 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 432CF20289C for ; Tue, 29 Mar 2022 05:40:34 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id u13-20020a50a40d000000b00419028f7f96so10939301edb.21 for ; Tue, 29 Mar 2022 05:40:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=8AKHIAUMGhsnollvhsjHBd8Sk5jMCuogkkUw2fq2mio=; b=XcHMPrIunHEB7bnidvOWVqGkL2poJnCfl3iM5yKiBsKR6gSu8Wixo56EriIryx1DRp ygH60Tu95F9/meUZw/hUVe5ooSEvV4DUyL+AnjgINrfQqz23fqsQ/Urcza7iRtW9piEV THlnQvDWO68UWi/+f1lgxFSyUR51bTc8P/jVxtWV8kXPBWeM+/Vw42NYvsdPHbIvLwKl BtRHlbH4A6DhSIcH+duqkqgGkt1gIGp9zkGZLXy9w5ZW5bKRdMPnBS9mX2KVQ6Pv+KK4 P1gagNsItDlHvWIoB7ysOglwXcmuxg7hOzImH2QfoKH5JQ//E60JCop3/Ya58UM8UMrt o7bg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=8AKHIAUMGhsnollvhsjHBd8Sk5jMCuogkkUw2fq2mio=; b=bAC4x1R1Qp0F830lGnPL4+lPcK964lLDsCy9PMBYnVMUk76UiycJGYFIZGLmqpfIlu Ygabd2QdlnTnSvhbnaCGaK9+QjK5AWxTUrspjxgilxoTj+lSwWT60qzVIhtP/jln52a/ rc8Zw7dMs4NfzL0D/JEs94NLgXzuKpeWvvZx5pBVb6WCudXLcsaxEEvkRrtziG6RW5tO ONlyL3+qlYXZ6hhO/a/VclxWKkZ2ZqJHF1Ae3shAMypd6bS7iOxwES7Cer3WRpgHMpyZ PCDCop8pdpLjmb3A2TxHPu1DH2DWm2PhW4WHE+Maqses6/oOj7DlwMyB5Serbwj3tFWO W4/Q== X-Gm-Message-State: AOAM531xFArYAKVw7A4KdlLLj1ABPPiBzoJzm5pBoVN6UZe5HKqxZxaC WmntLrlj6XkGfezeL9j/SUOo7X+3hF0= X-Google-Smtp-Source: ABdhPJwvUW8uBcv5kN+9WJ7X27ALOaTkbkLM5E0yAmcoJPh2fi12GxrbHP+7afPcQ2MGB4Oun8BxCd/6FeU= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:5d03:b0:6df:a042:d6d5 with SMTP id g3-20020a1709065d0300b006dfa042d6d5mr33258222ejt.678.1648557633185; Tue, 29 Mar 2022 05:40:33 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:31 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-3-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 02/48] stackdepot: reserve 5 extra bits in depot_stack_handle_t From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Some users (currently only KMSAN) may want to use spare bits in depot_stack_handle_t. Let them do so by adding @extra_bits to __stack_depot_save() to store arbitrary flags, and providing stack_depot_get_extra_bits() to retrieve those flags. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I0587f6c777667864768daf07821= d594bce6d8ff9 --- include/linux/stackdepot.h | 8 ++++++++ lib/stackdepot.c | 29 ++++++++++++++++++++++++----- 2 files changed, 32 insertions(+), 5 deletions(-) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 17f992fe6355b..fd641d266bead 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -14,9 +14,15 @@ #include =20 typedef u32 depot_stack_handle_t; +/* + * Number of bits in the handle that stack depot doesn't use. Users may st= ore + * information in them. + */ +#define STACK_DEPOT_EXTRA_BITS 5 =20 depot_stack_handle_t __stack_depot_save(unsigned long *entries, unsigned int nr_entries, + unsigned int extra_bits, gfp_t gfp_flags, bool can_alloc); =20 /* @@ -41,6 +47,8 @@ depot_stack_handle_t stack_depot_save(unsigned long *entr= ies, unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries); =20 +unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle); + int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t siz= e, int spaces); =20 diff --git a/lib/stackdepot.c b/lib/stackdepot.c index bf5ba9af05009..6dc11a3b7b88e 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -42,7 +42,8 @@ #define STACK_ALLOC_OFFSET_BITS (STACK_ALLOC_ORDER + PAGE_SHIFT - \ STACK_ALLOC_ALIGN) #define STACK_ALLOC_INDEX_BITS (DEPOT_STACK_BITS - \ - STACK_ALLOC_NULL_PROTECTION_BITS - STACK_ALLOC_OFFSET_BITS) + STACK_ALLOC_NULL_PROTECTION_BITS - \ + STACK_ALLOC_OFFSET_BITS - STACK_DEPOT_EXTRA_BITS) #define STACK_ALLOC_SLABS_CAP 8192 #define STACK_ALLOC_MAX_SLABS \ (((1LL << (STACK_ALLOC_INDEX_BITS)) < STACK_ALLOC_SLABS_CAP) ? \ @@ -55,6 +56,7 @@ union handle_parts { u32 slabindex : STACK_ALLOC_INDEX_BITS; u32 offset : STACK_ALLOC_OFFSET_BITS; u32 valid : STACK_ALLOC_NULL_PROTECTION_BITS; + u32 extra : STACK_DEPOT_EXTRA_BITS; }; }; =20 @@ -73,6 +75,14 @@ static int next_slab_inited; static size_t depot_offset; static DEFINE_RAW_SPINLOCK(depot_lock); =20 +unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle) +{ + union handle_parts parts =3D { .handle =3D handle }; + + return parts.extra; +} +EXPORT_SYMBOL(stack_depot_get_extra_bits); + static bool init_stack_slab(void **prealloc) { if (!*prealloc) @@ -136,6 +146,7 @@ depot_alloc_stack(unsigned long *entries, int size, u32= hash, void **prealloc) stack->handle.slabindex =3D depot_index; stack->handle.offset =3D depot_offset >> STACK_ALLOC_ALIGN; stack->handle.valid =3D 1; + stack->handle.extra =3D 0; memcpy(stack->entries, entries, flex_array_size(stack, entries, size)); depot_offset +=3D required_size; =20 @@ -320,6 +331,7 @@ EXPORT_SYMBOL_GPL(stack_depot_fetch); * * @entries: Pointer to storage array * @nr_entries: Size of the storage array + * @extra_bits: Flags to store in unused bits of depot_stack_handle_t * @alloc_flags: Allocation gfp flags * @can_alloc: Allocate stack slabs (increased chance of failure if false) * @@ -331,6 +343,10 @@ EXPORT_SYMBOL_GPL(stack_depot_fetch); * If the stack trace in @entries is from an interrupt, only the portion u= p to * interrupt entry is saved. * + * Additional opaque flags can be passed in @extra_bits, stored in the unu= sed + * bits of the stack handle, and retrieved using stack_depot_get_extra_bit= s() + * without calling stack_depot_fetch(). + * * Context: Any context, but setting @can_alloc to %false is required if * alloc_pages() cannot be used from the current context. Current= ly * this is the case from contexts where neither %GFP_ATOMIC nor @@ -340,10 +356,11 @@ EXPORT_SYMBOL_GPL(stack_depot_fetch); */ depot_stack_handle_t __stack_depot_save(unsigned long *entries, unsigned int nr_entries, + unsigned int extra_bits, gfp_t alloc_flags, bool can_alloc) { struct stack_record *found =3D NULL, **bucket; - depot_stack_handle_t retval =3D 0; + union handle_parts retval =3D { .handle =3D 0 }; struct page *page =3D NULL; void *prealloc =3D NULL; unsigned long flags; @@ -427,9 +444,11 @@ depot_stack_handle_t __stack_depot_save(unsigned long = *entries, free_pages((unsigned long)prealloc, STACK_ALLOC_ORDER); } if (found) - retval =3D found->handle.handle; + retval.handle =3D found->handle.handle; fast_exit: - return retval; + retval.extra =3D extra_bits; + + return retval.handle; } EXPORT_SYMBOL_GPL(__stack_depot_save); =20 @@ -449,6 +468,6 @@ depot_stack_handle_t stack_depot_save(unsigned long *en= tries, unsigned int nr_entries, gfp_t alloc_flags) { - return __stack_depot_save(entries, nr_entries, alloc_flags, true); + return __stack_depot_save(entries, nr_entries, 0, alloc_flags, true); } EXPORT_SYMBOL_GPL(stack_depot_save); --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBEA7C433FE for ; Tue, 29 Mar 2022 12:40:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236400AbiC2Mmj (ORCPT ); Tue, 29 Mar 2022 08:42:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60334 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236388AbiC2MmY (ORCPT ); Tue, 29 Mar 2022 08:42:24 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 916AB204C9F for ; Tue, 29 Mar 2022 05:40:37 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id b71-20020a509f4d000000b00418d658e9d1so10842329edf.19 for ; Tue, 29 Mar 2022 05:40:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=hetjka8F+4smAU2DbrfLtuY9Keg4VAYWsS2h7SzTHpM=; b=cHcpM//qa8SvJJrjPOG9wtT4Hj5D6kD8ib68SB0Mqb0q0PO5BtYL9X9Qere7Y8XjxC bOM2jC9VPziu2bY4mbcytTILLbSgpj6V9GVCh6WxioXetMKQTjrwkM8t/un72VJ5Mtgo iN8edkLwGflJ0otqfb1a7ajaVSPA/j+RPaBGepgVwwsEbS3i0p4LMpfh/BW0+mkCnvMU Dy9dZon78osDnNaQChTznTJymR927G4ea5V6szrz6kTy1ZvwLWbYPa/cpH3vDDIjeqkx FCLP31BQXYYVkPw5/Wg74buUelJiPy1QB+ObNDqL4zRzTdeyCzo8GYIkh1l7+0BmBJHW d2Qg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=hetjka8F+4smAU2DbrfLtuY9Keg4VAYWsS2h7SzTHpM=; b=J4WzGm2HO1Z7sKMY89GJAws58lKdcUX3DaSfVJBtZbj0P7LqvS7ZGqRAnEy5tUfxyD +LM1z9MJib/m9JPkX6L2dJuq3vapBb8uyvEIC4m7mRNNcZ2OUa1YBCQ1qLPFtbr74/8R FWoWrtH+KRcKm5O09oY0xPscYy+oY1VwJMs1QxP48IabD8eOkyMyaZfICIe8JmjfS6WL Lhue5rO3LelUA4li4V0J2IUOJWpimuHJMmElob7AxDuyJUQETJlcp2hdJMo+JscfaFFW G2VTfyPs/EUNTXmT9wf54a6KWo0m9qUoy0Uz1J7LHtFMKNYDrFVijX/EU872q1/QJJy2 RyUw== X-Gm-Message-State: AOAM530XlJbi/3tBQMIB+lJrM8PKWhnNMsVgE+wXC0btaf+M5bhxtPhp 4vcptq88O99klUDkFLHfjTYa2R1zM94= X-Google-Smtp-Source: ABdhPJyG5Cqqhqcj/H0YOQo5c9+FB/qfdcBot+5TAfkkvUFt0c3NMnQ9bJxFD4PL2W5gYj33TH1h8vNqlJU= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:aa7:c3d6:0:b0:419:2370:4856 with SMTP id l22-20020aa7c3d6000000b0041923704856mr4374152edr.180.1648557635703; Tue, 29 Mar 2022 05:40:35 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:32 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-4-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 03/48] kasan: common: adapt to the new prototype of __stack_depot_save() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Pass extra_bits=3D0, as KASAN does not intend to store additional information in the stack handle. No functional change. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I932d8f4f11a41b7483e0d570787= 44cc94697607a --- mm/kasan/common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 92196562687b6..1182388ed3e0e 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -36,7 +36,7 @@ depot_stack_handle_t kasan_save_stack(gfp_t flags, bool c= an_alloc) unsigned int nr_entries; =20 nr_entries =3D stack_trace_save(entries, ARRAY_SIZE(entries), 0); - return __stack_depot_save(entries, nr_entries, flags, can_alloc); + return __stack_depot_save(entries, nr_entries, 0, flags, can_alloc); } =20 void kasan_set_track(struct kasan_track *track, gfp_t flags) --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F1E2C433FE for ; Tue, 29 Mar 2022 12:41:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236437AbiC2Mmx (ORCPT ); Tue, 29 Mar 2022 08:42:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236386AbiC2MmY (ORCPT ); Tue, 29 Mar 2022 08:42:24 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49240208262 for ; Tue, 29 Mar 2022 05:40:40 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id jx2-20020a170907760200b006dfc374c502so8133399ejc.7 for ; Tue, 29 Mar 2022 05:40:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=ZbpkAPrcek/iQP5wGrULo2GyXUubszl45zwfN6Jeluw=; b=ItupbKsXf4T5DY5u/yeeKCGIvUjyF/GlXb2acWFwSqEwOouWQJJd75u+lYjEdhwRsk x0pI62vVhg0Y4u8RI7UIPJU/Eqf79K9v97zc3PIqXZQTcfivaabLsxtwYPpNXZLOPN7A SZgOBkXKV3f84Llcqxo97iq6zKz+d2axtqQlOBgHN8rf8y82br0aiI2/9LCooptaQgPP P6ZvYfs4FbSv6hARDwyXMbcMlkWQVBNPbA/3Uoza/8Y05ryJE2Lr1VFxEJTMSrLmTfM4 jNRCJOZhJMXJQQuPXIpHYeQ3+puw+pEYGw6AQKRq8/qV73cd1+HEYhRSrqN+H56zMEzh Uy5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ZbpkAPrcek/iQP5wGrULo2GyXUubszl45zwfN6Jeluw=; b=rDKP38eDnrjwXTL4G1kQnTWXGOVhvKXZ2MyhrCk4GyrGHPVT8vm7y5rI1o8nSrMWFN 3jbrFHOcUs193X1XI8T1/Jxn3i6aVLdiOICnxEykSejFT1dZ2PTjyemm9qHXyr9cHPO6 z5i1uUDY/+0RC7rHTzRWy9vfr49VcVAzLK6uy59RkuWE6dqOoeouQsld6VaBlTKYNsvT 3Vh1syQX65ART2zZQTeiTuz2Z1emu1A5W0qH705GskFSuuMe++v2UE51qxefIl39C2TM 7WZ/Bd88x0ATkiRkADWZdFxRc8SUSKT+KuyESe84b+vIc2h3N0hE0K0vMpGvFWSKd0fg aIKg== X-Gm-Message-State: AOAM5318Z8cPBsRJeDf9C31b8SUy2vxBiEKcEVCKzfOd4qH/rb/dKRvF vAuGFtGaZpihTLYaakU9qKnheUSU2cI= X-Google-Smtp-Source: ABdhPJzbGaMHRSN6Foq0MN7pYOwtpEK1d+tqys1HKVelbpVg4A40evROqReC43MTXMy6pYq67i6tt1aBecs= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:dc8b:b0:6df:7a71:1321 with SMTP id cs11-20020a170906dc8b00b006df7a711321mr33531777ejc.476.1648557638735; Tue, 29 Mar 2022 05:40:38 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:33 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-5-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 04/48] instrumented.h: allow instrumenting both sides of copy_from_user() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Introduce instrument_copy_from_user_before() and instrument_copy_from_user_after() hooks to be invoked before and after the call to copy_from_user(). KASAN and KCSAN will be only using instrument_copy_from_user_before(), but for KMSAN we'll need to insert code after copy_from_user(). Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I855034578f0b0f126734cbd734f= b4ae1d3a6af99 --- include/linux/instrumented.h | 21 +++++++++++++++++++-- include/linux/uaccess.h | 19 ++++++++++++++----- lib/iov_iter.c | 9 ++++++--- lib/usercopy.c | 3 ++- 4 files changed, 41 insertions(+), 11 deletions(-) diff --git a/include/linux/instrumented.h b/include/linux/instrumented.h index 42faebbaa202a..ee8f7d17d34f5 100644 --- a/include/linux/instrumented.h +++ b/include/linux/instrumented.h @@ -120,7 +120,7 @@ instrument_copy_to_user(void __user *to, const void *fr= om, unsigned long n) } =20 /** - * instrument_copy_from_user - instrument writes of copy_from_user + * instrument_copy_from_user_before - add instrumentation before copy_from= _user * * Instrument writes to kernel memory, that are due to copy_from_user (and * variants). The instrumentation should be inserted before the accesses. @@ -130,10 +130,27 @@ instrument_copy_to_user(void __user *to, const void *= from, unsigned long n) * @n number of bytes to copy */ static __always_inline void -instrument_copy_from_user(const void *to, const void __user *from, unsigne= d long n) +instrument_copy_from_user_before(const void *to, const void __user *from, = unsigned long n) { kasan_check_write(to, n); kcsan_check_write(to, n); } =20 +/** + * instrument_copy_from_user_after - add instrumentation after copy_from_u= ser + * + * Instrument writes to kernel memory, that are due to copy_from_user (and + * variants). The instrumentation should be inserted after the accesses. + * + * @to destination address + * @from source address + * @n number of bytes to copy + * @left number of bytes not copied (as returned by copy_from_user) + */ +static __always_inline void +instrument_copy_from_user_after(const void *to, const void __user *from, + unsigned long n, unsigned long left) +{ +} + #endif /* _LINUX_INSTRUMENTED_H */ diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index ac0394087f7d4..8dadd8642afbb 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -98,20 +98,28 @@ static inline void force_uaccess_end(mm_segment_t oldfs) static __always_inline __must_check unsigned long __copy_from_user_inatomic(void *to, const void __user *from, unsigned long= n) { - instrument_copy_from_user(to, from, n); + unsigned long res; + + instrument_copy_from_user_before(to, from, n); check_object_size(to, n, false); - return raw_copy_from_user(to, from, n); + res =3D raw_copy_from_user(to, from, n); + instrument_copy_from_user_after(to, from, n, res); + return res; } =20 static __always_inline __must_check unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n) { + unsigned long res; + might_fault(); + instrument_copy_from_user_before(to, from, n); if (should_fail_usercopy()) return n; - instrument_copy_from_user(to, from, n); check_object_size(to, n, false); - return raw_copy_from_user(to, from, n); + res =3D raw_copy_from_user(to, from, n); + instrument_copy_from_user_after(to, from, n, res); + return res; } =20 /** @@ -155,8 +163,9 @@ _copy_from_user(void *to, const void __user *from, unsi= gned long n) unsigned long res =3D n; might_fault(); if (!should_fail_usercopy() && likely(access_ok(from, n))) { - instrument_copy_from_user(to, from, n); + instrument_copy_from_user_before(to, from, n); res =3D raw_copy_from_user(to, from, n); + instrument_copy_from_user_after(to, from, n, res); } if (unlikely(res)) memset(to + (n - res), 0, res); diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 6dd5330f7a995..fb19401c29c4f 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -159,13 +159,16 @@ static int copyout(void __user *to, const void *from,= size_t n) =20 static int copyin(void *to, const void __user *from, size_t n) { + size_t res =3D n; + if (should_fail_usercopy()) return n; if (access_ok(from, n)) { - instrument_copy_from_user(to, from, n); - n =3D raw_copy_from_user(to, from, n); + instrument_copy_from_user_before(to, from, n); + res =3D raw_copy_from_user(to, from, n); + instrument_copy_from_user_after(to, from, n, res); } - return n; + return res; } =20 static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, si= ze_t bytes, diff --git a/lib/usercopy.c b/lib/usercopy.c index 7413dd300516e..1505a52f23a01 100644 --- a/lib/usercopy.c +++ b/lib/usercopy.c @@ -12,8 +12,9 @@ unsigned long _copy_from_user(void *to, const void __user= *from, unsigned long n unsigned long res =3D n; might_fault(); if (!should_fail_usercopy() && likely(access_ok(from, n))) { - instrument_copy_from_user(to, from, n); + instrument_copy_from_user_before(to, from, n); res =3D raw_copy_from_user(to, from, n); + instrument_copy_from_user_after(to, from, n, res); } if (unlikely(res)) memset(to + (n - res), 0, res); --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 00CD5C433FE for ; Tue, 29 Mar 2022 12:41:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236572AbiC2MnR (ORCPT ); Tue, 29 Mar 2022 08:43:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236415AbiC2Mm0 (ORCPT ); Tue, 29 Mar 2022 08:42:26 -0400 Received: from mail-ed1-x54a.google.com (mail-ed1-x54a.google.com [IPv6:2a00:1450:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 057C9204A9E for ; Tue, 29 Mar 2022 05:40:42 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id c22-20020a50f616000000b004196649d144so10955874edn.10 for ; Tue, 29 Mar 2022 05:40:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=3RM0qhEhF66BtuM0ZXwaEhPbHnfCR09wU8nC/pTqHi8=; b=ZfQ96zQsPsKfBQ/c9B+p0T/40FovJz4CFLCUEiSSbflULpKaBSwZh18ccdw9FjFMR/ 6CL212sJnEyxZj6LrueXeIA3af+ha93f5SXcMHFxIvZ8XcaA3jgjh2CgfsWeI5aC/FoO SsZxN2XfUHXoWAeOjgXaOjO75UgBK6Rk75Jr8fIsEu0Ij5ADYX0ek6w89sp3ufSZz+VH z3XgZl5AChOAcBCeLORpdjPovuJuV3Q3SgS4VWwGIZ606KqelRUzogETo02XK3PN9Ui9 gob299cB95qVQVVfrCpMAbauzPoQU2jiYcZtRwKNYM8m/tLM7wpaFE+a7CQHD2mcjmDA fVYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=3RM0qhEhF66BtuM0ZXwaEhPbHnfCR09wU8nC/pTqHi8=; b=RshM1hgneStUYDcxZKPEQjDm8Jf72u7Ng2rnsOdMzp42NlIKYktpJT+vB/2LifcEl8 OiLc0prfZwBPbGNFoBEL+K2NtPqk294z52a3x18E28XJwewvQv6XIr3zolr2QHnzAFKz geRjaL8aWKAc3quTTL1WAPHcCl+Rlqwd7QkmaX53BNZCatSGymh1Btuc0+sbLjzKsZlB t+ewkvC3yDSJx1FSPBY1VoDaOUBo6pVY5gR6mhummYoVRGMqSkQ7yQoPSZQkdfXJGmWF pd5hinkH8McEydcnyt5x/AsYgh4wuRUKt4pMbgBlQtNR+q+gsZzcGqqP+edL00NsmvS8 UDbQ== X-Gm-Message-State: AOAM531jk26EzQ+dWLWu9TZ75HJ5GXmf0iwkJnKG1AMErNiolrgXRuGl dMhCYn18YcCuHLcWw7nQmj+PYLRpZzs= X-Google-Smtp-Source: ABdhPJxZVbkRLRuOZHRe+6vIay7XNPuEELMpuQ9mw5W8uiPx5u+x394b7lBiwbP526tqAx4KRk6EWhiX5Zw= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:2ce3:b0:6df:d4a8:9039 with SMTP id hz3-20020a1709072ce300b006dfd4a89039mr33974181ejc.697.1648557641243; Tue, 29 Mar 2022 05:40:41 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:34 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-6-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 05/48] x86: asm: instrument usercopy in get_user() and __put_user_size() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Use hooks from instrumented.h to notify bug detection tools about usercopy events in get_user() and put_user_size(). It's still unclear how to instrument put_user(), which assumes that instrumentation code doesn't clobber RAX. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Ia9f12bfe5832623250e20f1859f= df5cc485a2fce --- arch/x86/include/asm/uaccess.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index ac96f9b2d64b3..e6abe6f27ae99 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -5,6 +5,7 @@ * User space memory access functions */ #include +#include #include #include #include @@ -126,11 +127,13 @@ extern int __get_user_bad(void); int __ret_gu; \ register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \ __chk_user_ptr(ptr); \ + instrument_copy_from_user_before((void *)&(x), ptr, sizeof(*(ptr))); \ asm volatile("call __" #fn "_%P4" \ : "=3Da" (__ret_gu), "=3Dr" (__val_gu), \ ASM_CALL_CONSTRAINT \ : "0" (ptr), "i" (sizeof(*(ptr)))); \ (x) =3D (__force __typeof__(*(ptr))) __val_gu; \ + instrument_copy_from_user_after((void *)&(x), ptr, sizeof(*(ptr)), 0); \ __builtin_expect(__ret_gu, 0); \ }) =20 @@ -275,7 +278,9 @@ extern void __put_user_nocheck_8(void); =20 #define __put_user_size(x, ptr, size, label) \ do { \ + __typeof__(*(ptr)) __pus_val =3D x; \ __chk_user_ptr(ptr); \ + instrument_copy_to_user(ptr, &(__pus_val), size); \ switch (size) { \ case 1: \ __put_user_goto(x, ptr, "b", "iq", label); \ @@ -313,6 +318,7 @@ do { \ #define __get_user_size(x, ptr, size, label) \ do { \ __chk_user_ptr(ptr); \ + instrument_copy_from_user_before((void *)&(x), ptr, size); \ switch (size) { \ case 1: { \ unsigned char x_u8__; \ @@ -332,6 +338,7 @@ do { \ default: \ (x) =3D __get_user_bad(); \ } \ + instrument_copy_from_user_after((void *)&(x), ptr, size, 0); \ } while (0) =20 #define __get_user_asm(x, addr, itype, ltype, label) \ --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 24760C433F5 for ; Tue, 29 Mar 2022 12:41:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236564AbiC2MnK (ORCPT ); Tue, 29 Mar 2022 08:43:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236433AbiC2Mmi (ORCPT ); Tue, 29 Mar 2022 08:42:38 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD0A120D80D for ; Tue, 29 Mar 2022 05:40:45 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id h22-20020a1709060f5600b006b11a2d3dcfso8124999ejj.4 for ; Tue, 29 Mar 2022 05:40:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=f/cngww90lUXjaM8lQFtWcyKhuwI9PqnftLYJV81Lhc=; b=ZhkI15SJzz773ZYscrUiWSWJETsRZFPteEYHqIHePZDMxUIF+3PQF+2Fw76owrqA6c UPmlNmwXK1Z6638+mZDSIi3ZaYImXqe+Uh0pSLh1rhQp3Xoe7jl74OrGzrvEG7z0eTSq o8MSM+eKeJVRDYa5y/OP8y60rroWEDJ8vzz/DDepligD6r9qfkOI3I92z4rW1hHLRtic cm0rD0pMAAL/xX1aSmAtPrmorukG9QpyLNGeNh6R44fL+JlPunKHnHJWEF85pS921n3e lbvxIMwP6/gs5F0Sdc52ZKShD71Ts7NFaxuC1noz1+PVJK55QErm2j6Lz/PX6SBoULEe K4FA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=f/cngww90lUXjaM8lQFtWcyKhuwI9PqnftLYJV81Lhc=; b=kgWDWGGoMJmPw0I2QTLd1mukTZ3katdjzpKxEUi7XlQCMiJ2e2d7SovZDYc1FP9Juu p6K1C5oY7yQQJoj8D7R4SXKYlYi5QdzkfaXRlp30PnZteKU+GP3qL8KLTadA65sFSibH PWGSD1Z+N5CCk+4Ilhb+haSYnMOaX35fSTOuQgC/RUht582yxxELIa9ENvFkmNXGWqob RqFpX4vzNpZQNdHBb9ZQ+Ll6IF4FZrlO07Sb9nLs9J91EBpYW45zia9rmCpQKq4k8H4b ecG9bRXbiB4NvJdmoeXL5CdYvthBBz6L52IAUAx6C26evxoe/CFNlxPqZG6CND7pWm73 gqwQ== X-Gm-Message-State: AOAM532wv4tEM9sSlm9UumoApDX4ScopNYwEbwujN+mUEbBcXHLQdPxP UaB4VrkApg24VdHn+6lznvCmy7BfOoU= X-Google-Smtp-Source: ABdhPJx0Sl5gQKr3lXwaLxCri9MHvRT0DK5gtdgM1us4GPzvAAhQsz1qiosUClgYfwn1c4jOcnHsaUZStL0= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:478e:b0:6db:7c67:c7e0 with SMTP id cw14-20020a170906478e00b006db7c67c7e0mr34151057ejc.335.1648557643821; Tue, 29 Mar 2022 05:40:43 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:35 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-7-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 06/48] asm-generic: instrument usercopy in cacheflush.h From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Notify memory tools about usercopy events in copy_to_user_page() and copy_from_user_page(). Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Ic1ee8da1886325f46ad67f52176= f48c2c836c48f --- include/asm-generic/cacheflush.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/include/asm-generic/cacheflush.h b/include/asm-generic/cachefl= ush.h index 4f07afacbc239..0f63eb325025f 100644 --- a/include/asm-generic/cacheflush.h +++ b/include/asm-generic/cacheflush.h @@ -2,6 +2,8 @@ #ifndef _ASM_GENERIC_CACHEFLUSH_H #define _ASM_GENERIC_CACHEFLUSH_H =20 +#include + struct mm_struct; struct vm_area_struct; struct page; @@ -105,6 +107,7 @@ static inline void flush_cache_vunmap(unsigned long sta= rt, unsigned long end) #ifndef copy_to_user_page #define copy_to_user_page(vma, page, vaddr, dst, src, len) \ do { \ + instrument_copy_to_user(dst, src, len); \ memcpy(dst, src, len); \ flush_icache_user_page(vma, page, vaddr, len); \ } while (0) @@ -112,7 +115,11 @@ static inline void flush_cache_vunmap(unsigned long st= art, unsigned long end) =20 #ifndef copy_from_user_page #define copy_from_user_page(vma, page, vaddr, dst, src, len) \ - memcpy(dst, src, len) + do { \ + instrument_copy_from_user_before(dst, src, len); \ + memcpy(dst, src, len); \ + instrument_copy_from_user_after(dst, src, len, 0); \ + } while (0) #endif =20 #endif /* _ASM_GENERIC_CACHEFLUSH_H */ --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D869BC433EF for ; Tue, 29 Mar 2022 12:41:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236478AbiC2MnH (ORCPT ); Tue, 29 Mar 2022 08:43:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236451AbiC2Mmq (ORCPT ); Tue, 29 Mar 2022 08:42:46 -0400 Received: from mail-ej1-x64a.google.com (mail-ej1-x64a.google.com [IPv6:2a00:1450:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 430C8211EF2 for ; Tue, 29 Mar 2022 05:40:49 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id ml20-20020a170906cc1400b006df8c9357efso8110272ejb.21 for ; Tue, 29 Mar 2022 05:40:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=TN/IxFbfYSJBoxieUM3SQ/pLsTFSHtJCIFgRUhWzQ6I=; b=MnJm4q0Qbv0TnFel33gkHsMyPpqBzj6o4FjUDU9yREtrg/KJit6EMVlNBddwodEznp 9S/YExh8KAnG5MFuNoqTaCHTikpdeTZCx5ddPmPXcU7y7f323Ny6zx4cB/oW22PlgVp1 N9FdxrsPSJIs7UTsl0O/uURvZoDBKd1KJ2pkSHdSUPP3zoG/hYqbLwoiEIAeyA/SVmWu GzbIGSsiud+Ez7lsIrPLktyDvbHo0wrESSZgBAuuyd6XOg8jLBaDQBGOmCH4fEusE35f wkWki3WLYgFyOiUIpwDBmhnOXoitFGvVOucWvWVKtbIlLbypUvpkVbk00fuFCx66hV/4 TJPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=TN/IxFbfYSJBoxieUM3SQ/pLsTFSHtJCIFgRUhWzQ6I=; b=t8+GusWlpHqJJ5jUOeH7WfQzEE1LpB4RzGf7N+OxsTk5KJKA+gO3doUUWn8BRdmhfF ieQtFQfpRj/oCCpbbMuMu+d32ANKu1ySy4PxHgOB5xyqDnwaTtmSuR+iB0VWvMuJbJAe 0QjJ1OXW22/yC4FxRO4+XiDlk+lQQ9VRz2RH9ztIjlHzfDc6U4PSTdTWjAML6c5rBPfN c5fd/MiN/FJ6kQdEuAAu27Z6keiBRdg9hfesIRj/EOgPeK+xGHNlp+39ji6ZyTRdqSpJ hFGW2nUtE+6esGOYqGHHsj/3MYbBqYLxECp4/+kB5Yu79hQzk/ZH+mXdTZtyHlpCB7fI TuKA== X-Gm-Message-State: AOAM532FiJhXyttSQQjhmvAcIPw/aC25oVvTPEGemAT8EFzRVcJVGrto 502+2kumb+vt+aZNdh/iFjUsDZ6QG3c= X-Google-Smtp-Source: ABdhPJyn/oA1l/U2fo5rey9KTTtH1HuAy5KcTBb2H/xsbD/q94GXmO05dXXU6kGFMH+oU3N7aSmJpMEhwCI= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:72cc:b0:6e0:2d3:bcba with SMTP id du12-20020a17090772cc00b006e002d3bcbamr34220627ejc.642.1648557646754; Tue, 29 Mar 2022 05:40:46 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:36 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-8-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 07/48] kmsan: add ReST documentation From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add Documentation/dev-tools/kmsan.rst and reference it in the dev-tools index. Signed-off-by: Alexander Potapenko --- v2: -- added a note that KMSAN is not intended for production use Link: https://linux-review.googlesource.com/id/I751586f79418b95550a83c6035c= 650b5b01567cc --- Documentation/dev-tools/index.rst | 1 + Documentation/dev-tools/kmsan.rst | 414 ++++++++++++++++++++++++++++++ 2 files changed, 415 insertions(+) create mode 100644 Documentation/dev-tools/kmsan.rst diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/in= dex.rst index 4621eac290f46..6b0663075dc04 100644 --- a/Documentation/dev-tools/index.rst +++ b/Documentation/dev-tools/index.rst @@ -24,6 +24,7 @@ Documentation/dev-tools/testing-overview.rst kcov gcov kasan + kmsan ubsan kmemleak kcsan diff --git a/Documentation/dev-tools/kmsan.rst b/Documentation/dev-tools/km= san.rst new file mode 100644 index 0000000000000..e116889da79d5 --- /dev/null +++ b/Documentation/dev-tools/kmsan.rst @@ -0,0 +1,414 @@ +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D +KernelMemorySanitizer (KMSAN) +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D + +KMSAN is a dynamic error detector aimed at finding uses of uninitialized +values. It is based on compiler instrumentation, and is quite similar to t= he +userspace `MemorySanitizer tool`_. + +An important note is that KMSAN is not intended for production use, becaus= e it +drastically increases kernel memory footprint and slows the whole system d= own. + +Example report +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +Here is an example of a KMSAN report:: + + =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D + BUG: KMSAN: uninit-value in test_uninit_kmsan_check_memory+0x1be/0x380 [= kmsan_test] + test_uninit_kmsan_check_memory+0x1be/0x380 mm/kmsan/kmsan_test.c:273 + kunit_run_case_internal lib/kunit/test.c:333 + kunit_try_run_case+0x206/0x420 lib/kunit/test.c:374 + kunit_generic_run_threadfn_adapter+0x6d/0xc0 lib/kunit/try-catch.c:28 + kthread+0x721/0x850 kernel/kthread.c:327 + ret_from_fork+0x1f/0x30 ??:? + + Uninit was stored to memory at: + do_uninit_local_array+0xfa/0x110 mm/kmsan/kmsan_test.c:260 + test_uninit_kmsan_check_memory+0x1a2/0x380 mm/kmsan/kmsan_test.c:271 + kunit_run_case_internal lib/kunit/test.c:333 + kunit_try_run_case+0x206/0x420 lib/kunit/test.c:374 + kunit_generic_run_threadfn_adapter+0x6d/0xc0 lib/kunit/try-catch.c:28 + kthread+0x721/0x850 kernel/kthread.c:327 + ret_from_fork+0x1f/0x30 ??:? + + Local variable uninit created at: + do_uninit_local_array+0x4a/0x110 mm/kmsan/kmsan_test.c:256 + test_uninit_kmsan_check_memory+0x1a2/0x380 mm/kmsan/kmsan_test.c:271 + + Bytes 4-7 of 8 are uninitialized + Memory access of size 8 starts at ffff888083fe3da0 + + CPU: 0 PID: 6731 Comm: kunit_try_catch Tainted: G B E 5.16.= 0-rc3+ #104 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/= 01/2014 + =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D + + +The report says that the local variable ``uninit`` was created uninitializ= ed in +``do_uninit_local_array()``. The lower stack trace corresponds to the place +where this variable was created. + +The upper stack shows where the uninit value was used - in +``test_uninit_kmsan_check_memory()``. The tool shows the bytes which were = left +uninitialized in the local variable, as well as the stack where the value = was +copied to another memory location before use. + +Please note that KMSAN only reports an error when an uninitialized value is +actually used (e.g. in a condition or pointer dereference). A lot of +uninitialized values in the kernel are never used, and reporting them would +result in too many false positives. + +KMSAN and Clang +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +In order for KMSAN to work the kernel must be built with Clang, which so f= ar is +the only compiler that has KMSAN support. The kernel instrumentation pass = is +based on the userspace `MemorySanitizer tool`_. + +How to build +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +In order to build a kernel with KMSAN you will need a fresh Clang (14.0.0+= ). +Please refer to `LLVM documentation`_ for the instructions on how to build= Clang. + +Now configure and build the kernel with CONFIG_KMSAN enabled. + +How KMSAN works +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +KMSAN shadow memory +------------------- + +KMSAN associates a metadata byte (also called shadow byte) with every byte= of +kernel memory. A bit in the shadow byte is set iff the corresponding bit o= f the +kernel memory byte is uninitialized. Marking the memory uninitialized (i.e. +setting its shadow bytes to ``0xff``) is called poisoning, marking it +initialized (setting the shadow bytes to ``0x00``) is called unpoisoning. + +When a new variable is allocated on the stack, it is poisoned by default by +instrumentation code inserted by the compiler (unless it is a stack variab= le +that is immediately initialized). Any new heap allocation done without +``__GFP_ZERO`` is also poisoned. + +Compiler instrumentation also tracks the shadow values with the help from = the +runtime library in ``mm/kmsan/``. + +The shadow value of a basic or compound type is an array of bytes of the s= ame +length. When a constant value is written into memory, that memory is unpoi= soned. +When a value is read from memory, its shadow memory is also obtained and +propagated into all the operations which use that value. For every instruc= tion +that takes one or more values the compiler generates code that calculates = the +shadow of the result depending on those values and their shadows. + +Example:: + + int a =3D 0xff; // i.e. 0x000000ff + int b; + int c =3D a | b; + +In this case the shadow of ``a`` is ``0``, shadow of ``b`` is ``0xffffffff= ``, +shadow of ``c`` is ``0xffffff00``. This means that the upper three bytes of +``c`` are uninitialized, while the lower byte is initialized. + + +Origin tracking +--------------- + +Every four bytes of kernel memory also have a so-called origin assigned to +them. This origin describes the point in program execution at which the +uninitialized value was created. Every origin is associated with either the +full allocation stack (for heap-allocated memory), or the function contain= ing +the uninitialized variable (for locals). + +When an uninitialized variable is allocated on stack or heap, a new origin +value is created, and that variable's origin is filled with that value. +When a value is read from memory, its origin is also read and kept together +with the shadow. For every instruction that takes one or more values the o= rigin +of the result is one of the origins corresponding to any of the uninitiali= zed +inputs. If a poisoned value is written into memory, its origin is written = to the +corresponding storage as well. + +Example 1:: + + int a =3D 42; + int b; + int c =3D a + b; + +In this case the origin of ``b`` is generated upon function entry, and is +stored to the origin of ``c`` right before the addition result is written = into +memory. + +Several variables may share the same origin address, if they are stored in= the +same four-byte chunk. In this case every write to either variable updates = the +origin for all of them. We have to sacrifice precision in this case, becau= se +storing origins for individual bits (and even bytes) would be too costly. + +Example 2:: + + int combine(short a, short b) { + union ret_t { + int i; + short s[2]; + } ret; + ret.s[0] =3D a; + ret.s[1] =3D b; + return ret.i; + } + +If ``a`` is initialized and ``b`` is not, the shadow of the result would be +0xffff0000, and the origin of the result would be the origin of ``b``. +``ret.s[0]`` would have the same origin, but it will be never used, because +that variable is initialized. + +If both function arguments are uninitialized, only the origin of the second +argument is preserved. + +Origin chaining +~~~~~~~~~~~~~~~ + +To ease debugging, KMSAN creates a new origin for every store of an +uninitialized value to memory. The new origin references both its creation= stack +and the previous origin the value had. This may cause increased memory +consumption, so we limit the length of origin chains in the runtime. + +Clang instrumentation API +------------------------- + +Clang instrumentation pass inserts calls to functions defined in +``mm/kmsan/instrumentation.c`` into the kernel code. + +Shadow manipulation +~~~~~~~~~~~~~~~~~~~ + +For every memory access the compiler emits a call to a function that retur= ns a +pair of pointers to the shadow and origin addresses of the given memory:: + + typedef struct { + void *shadow, *origin; + } shadow_origin_ptr_t + + shadow_origin_ptr_t __msan_metadata_ptr_for_load_{1,2,4,8}(void *addr) + shadow_origin_ptr_t __msan_metadata_ptr_for_store_{1,2,4,8}(void *addr) + shadow_origin_ptr_t __msan_metadata_ptr_for_load_n(void *addr, uintptr_t= size) + shadow_origin_ptr_t __msan_metadata_ptr_for_store_n(void *addr, uintptr_= t size) + +The function name depends on the memory access size. + +The compiler makes sure that for every loaded value its shadow and origin +values are read from memory. When a value is stored to memory, its shadow = and +origin are also stored using the metadata pointers. + +Origin tracking +~~~~~~~~~~~~~~~ + +A special function is used to create a new origin value for a local variab= le and +set the origin of that variable to that value:: + + void __msan_poison_alloca(void *addr, uintptr_t size, char *descr) + +Access to per-task data +~~~~~~~~~~~~~~~~~~~~~~~~~ + +At the beginning of every instrumented function KMSAN inserts a call to +``__msan_get_context_state()``:: + + kmsan_context_state *__msan_get_context_state(void) + +``kmsan_context_state`` is declared in ``include/linux/kmsan.h``:: + + struct kmsan_context_state { + char param_tls[KMSAN_PARAM_SIZE]; + char retval_tls[KMSAN_RETVAL_SIZE]; + char va_arg_tls[KMSAN_PARAM_SIZE]; + char va_arg_origin_tls[KMSAN_PARAM_SIZE]; + u64 va_arg_overflow_size_tls; + char param_origin_tls[KMSAN_PARAM_SIZE]; + depot_stack_handle_t retval_origin_tls; + }; + +This structure is used by KMSAN to pass parameter shadows and origins betw= een +instrumented functions. + +String functions +~~~~~~~~~~~~~~~~ + +The compiler replaces calls to ``memcpy()``/``memmove()``/``memset()`` wit= h the +following functions. These functions are also called when data structures = are +initialized or copied, making sure shadow and origin values are copied alo= ngside +with the data:: + + void *__msan_memcpy(void *dst, void *src, uintptr_t n) + void *__msan_memmove(void *dst, void *src, uintptr_t n) + void *__msan_memset(void *dst, int c, uintptr_t n) + +Error reporting +~~~~~~~~~~~~~~~ + +For each pointer dereference and each condition the compiler emits a shadow +check that calls ``__msan_warning()`` in the case a poisoned value is being +used:: + + void __msan_warning(u32 origin) + +``__msan_warning()`` causes KMSAN runtime to print an error report. + +Inline assembly instrumentation +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +KMSAN instruments every inline assembly output with a call to:: + + void __msan_instrument_asm_store(void *addr, uintptr_t size) + +, which unpoisons the memory region. + +This approach may mask certain errors, but it also helps to avoid a lot of +false positives in bitwise operations, atomics etc. + +Sometimes the pointers passed into inline assembly do not point to valid m= emory. +In such cases they are ignored at runtime. + +Disabling the instrumentation +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +A function can be marked with ``__no_kmsan_checks``. Doing so makes KMSAN +ignore uninitialized values in that function and mark its output as initia= lized. +As a result, the user will not get KMSAN reports related to that function. + +Another function attribute supported by KMSAN is ``__no_sanitize_memory``. +Applying this attribute to a function will result in KMSAN not instrumenti= ng it, +which can be helpful if we do not want the compiler to mess up some low-le= vel +code (e.g. that marked with ``noinstr``). + +This however comes at a cost: stack allocations from such functions will h= ave +incorrect shadow/origin values, likely leading to false positives. Functio= ns +called from non-instrumented code may also receive incorrect metadata for = their +parameters. + +As a rule of thumb, avoid using ``__no_sanitize_memory`` explicitly. + +It is also possible to disable KMSAN for a single file (e.g. main.o):: + + KMSAN_SANITIZE_main.o :=3D n + +or for the whole directory:: + + KMSAN_SANITIZE :=3D n + +in the Makefile. Think of this as applying ``__no_sanitize_memory`` to eve= ry +function in the file or directory. Most users won't need KMSAN_SANITIZE, u= nless +their code gets broken by KMSAN (e.g. runs at early boot time). + +Runtime library +--------------- + +The code is located in ``mm/kmsan/``. + +Per-task KMSAN state +~~~~~~~~~~~~~~~~~~~~ + +Every task_struct has an associated KMSAN task state that holds the KMSAN +context (see above) and a per-task flag disallowing KMSAN reports:: + + struct kmsan_context { + ... + bool allow_reporting; + struct kmsan_context_state cstate; + ... + } + + struct task_struct { + ... + struct kmsan_context kmsan; + ... + } + + +KMSAN contexts +~~~~~~~~~~~~~~ + +When running in a kernel task context, KMSAN uses ``current->kmsan.cstate`= ` to +hold the metadata for function parameters and return values. + +But in the case the kernel is running in the interrupt, softirq or NMI con= text, +where ``current`` is unavailable, KMSAN switches to per-cpu interrupt stat= e:: + + DEFINE_PER_CPU(struct kmsan_ctx, kmsan_percpu_ctx); + +Metadata allocation +~~~~~~~~~~~~~~~~~~~ + +There are several places in the kernel for which the metadata is stored. + +1. Each ``struct page`` instance contains two pointers to its shadow and +origin pages:: + + struct page { + ... + struct page *shadow, *origin; + ... + }; + +At boot-time, the kernel allocates shadow and origin pages for every avail= able +kernel page. This is done quite late, when the kernel address space is alr= eady +fragmented, so normal data pages may arbitrarily interleave with the metad= ata +pages. + +This means that in general for two contiguous memory pages their shadow/or= igin +pages may not be contiguous. So, if a memory access crosses the boundary +of a memory block, accesses to shadow/origin memory may potentially corrupt +other pages or read incorrect values from them. + +In practice, contiguous memory pages returned by the same ``alloc_pages()`` +call will have contiguous metadata, whereas if these pages belong to two +different allocations their metadata pages can be fragmented. + +For the kernel data (``.data``, ``.bss`` etc.) and percpu memory regions +there also are no guarantees on metadata contiguity. + +In the case ``__msan_metadata_ptr_for_XXX_YYY()`` hits the border between = two +pages with non-contiguous metadata, it returns pointers to fake shadow/ori= gin regions:: + + char dummy_load_page[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE))); + char dummy_store_page[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE))); + +``dummy_load_page`` is zero-initialized, so reads from it always yield zer= oes. +All stores to ``dummy_store_page`` are ignored. + +2. For vmalloc memory and modules, there is a direct mapping between the m= emory +range, its shadow and origin. KMSAN reduces the vmalloc area by 3/4, makin= g only +the first quarter available to ``vmalloc()``. The second quarter of the vm= alloc +area contains shadow memory for the first quarter, the third one holds the +origins. A small part of the fourth quarter contains shadow and origins fo= r the +kernel modules. Please refer to ``arch/x86/include/asm/pgtable_64_types.h`= ` for +more details. + +When an array of pages is mapped into a contiguous virtual memory space, t= heir +shadow and origin pages are similarly mapped into contiguous regions. + +3. For CPU entry area there are separate per-CPU arrays that hold its +metadata:: + + DEFINE_PER_CPU(char[CPU_ENTRY_AREA_SIZE], cpu_entry_area_shadow); + DEFINE_PER_CPU(char[CPU_ENTRY_AREA_SIZE], cpu_entry_area_origin); + +When calculating shadow and origin addresses for a given memory address, K= MSAN +checks whether the address belongs to the physical page range, the virtual= page +range or CPU entry area. + +Handling ``pt_regs`` +~~~~~~~~~~~~~~~~~~~~ + +Many functions receive a ``struct pt_regs`` holding the register state at a +certain point. Registers do not have (easily calculatable) shadow or origin +associated with them, so we assume they are always initialized. + +References +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +E. Stepanov, K. Serebryany. `MemorySanitizer: fast detector of uninitializ= ed +memory use in C++ +`_. +In Proceedings of CGO 2015. + +.. _MemorySanitizer tool: https://clang.llvm.org/docs/MemorySanitizer.html +.. _LLVM documentation: https://llvm.org/docs/GettingStarted.html --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59B9AC433F5 for ; Tue, 29 Mar 2022 12:41:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236552AbiC2MnB (ORCPT ); Tue, 29 Mar 2022 08:43:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236455AbiC2Mmq (ORCPT ); Tue, 29 Mar 2022 08:42:46 -0400 Received: from mail-ed1-x54a.google.com (mail-ed1-x54a.google.com [IPv6:2a00:1450:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33911214058 for ; Tue, 29 Mar 2022 05:40:51 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id c22-20020a50f616000000b004196649d144so10956072edn.10 for ; Tue, 29 Mar 2022 05:40:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=UaSjyZbuX4mRK40KL0zvcfvrCfayHvnW+1lMpNenzMM=; b=pT67FL+iJPznO4FlucflrliCBhKvTTg3KzQEhmg/BoDC0PIplw3vRbgledaaV+22QV PJ/2UpcagqAHZUoUmS6KMEOgg3Z7MJ6MkNWm1ZXIgZy3JMhpaXGLkAOvgIFYB1qAJ0KF I6NW2lJcnoBn97EYtu4eiCl6ODsGpg3JBpDnaoBDHnydn7JC8QLk7eLmg2KpVSgBLImy ia3dXD2aOt8PinRoXSw+HiAUjr2cNNWGiXvsfmcUXKj+k0Ec0UTSj4Yj90p9F6jv5nLE 8q9nAN/NikHW+3ZZmHM89/rK8iQoXaim6KSGFGoalxm66Xa0wGT7M2cU/uJ7ZdLT9o7f Az0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=UaSjyZbuX4mRK40KL0zvcfvrCfayHvnW+1lMpNenzMM=; b=VVKPMFHkIqKbYAllYgjQG6cVpP4FpLX3A/EFIJE7w3bA7Hy9DoltBtdXnFWsAhDt1b 9WKMvIBknAo4R60PiLmk7fw6lWHQdKddl+jc6x9PDV776jr0R00Xy7wOxXmyGKdSnbbS zLzuwG5BSPu49eWHrKpeerL3o9u6XgL81zBvDIwcQ9cuG2MUy31I9EQD88e01WKkCila eTk30O1+dwysqJM5YvGPJ7yKGO1YDf1YlQbsvaceQduwMTmktOHxJ3slwAqY6y0Ovfyg lsfZALXi08qocmzyJd0sJz2FHH8dGXTm+QyLu/m8DP1g9HyktVIQZz+/r3tFKp/vSWcp VGZw== X-Gm-Message-State: AOAM532BFrZbasG0upeq2hM1gGTPWM+YZ5cBojqyPxu149vka9fyJZhd 65AebLcVTuSWxNUfxz0Ag64W8jP7ENA= X-Google-Smtp-Source: ABdhPJzc7uQQqv9/qIuIbMIwaZGD04hNlnYkXly8TbXNnnJOwrMOtsjceNSNZRkURUbxFzT9/MpcuG+W9FY= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a05:6402:1293:b0:418:fe9d:99c3 with SMTP id w19-20020a056402129300b00418fe9d99c3mr4374732edv.146.1648557649372; Tue, 29 Mar 2022 05:40:49 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:37 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-9-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 08/48] kmsan: introduce __no_sanitize_memory and __no_kmsan_checks From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" __no_sanitize_memory is a function attribute that instructs KMSAN to skip a function during instrumentation. This is needed to e.g. implement the noinstr functions. __no_kmsan_checks is a function attribute that makes KMSAN ignore the uninitialized values coming from the function's inputs, and initialize the function's outputs. Functions marked with this attribute can't be inlined into functions not marked with it, and vice versa. This behavior is overridden by __always_inline. __SANITIZE_MEMORY__ is a macro that's defined iff the file is instrumented with KMSAN. This is not the same as CONFIG_KMSAN, which is defined for every file. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I004ff0360c918d3cd8b18767ddd= 1381c6d3281be --- include/linux/compiler-clang.h | 23 +++++++++++++++++++++++ include/linux/compiler-gcc.h | 6 ++++++ 2 files changed, 29 insertions(+) diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index 3c4de9b6c6e3e..5f11a6f269e28 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -51,6 +51,29 @@ #define __no_sanitize_undefined #endif =20 +#if __has_feature(memory_sanitizer) +#define __SANITIZE_MEMORY__ +/* + * Unlike other sanitizers, KMSAN still inserts code into functions marked= with + * no_sanitize("kernel-memory"). Using disable_sanitizer_instrumentation + * provides the behavior consistent with other __no_sanitize_ attributes, + * guaranteeing that __no_sanitize_memory functions remain uninstrumented. + */ +#define __no_sanitize_memory __disable_sanitizer_instrumentation + +/* + * The __no_kmsan_checks attribute ensures that a function does not produce + * false positive reports by: + * - initializing all local variables and memory stores in this function; + * - skipping all shadow checks; + * - passing initialized arguments to this function's callees. + */ +#define __no_kmsan_checks __attribute__((no_sanitize("kernel-memory"))) +#else +#define __no_sanitize_memory +#define __no_kmsan_checks +#endif + /* * Support for __has_feature(coverage_sanitizer) was added in Clang 13 tog= ether * with no_sanitize("coverage"). Prior versions of Clang support coverage diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index ccbbd31b3aae5..f6e69387aad05 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -129,6 +129,12 @@ #define __SANITIZE_ADDRESS__ #endif =20 +/* + * GCC does not support KMSAN. + */ +#define __no_sanitize_memory +#define __no_kmsan_checks + /* * Turn individual warnings and errors on and off locally, depending * on version. --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 792D4C433F5 for ; Tue, 29 Mar 2022 12:41:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236510AbiC2Mnb (ORCPT ); Tue, 29 Mar 2022 08:43:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236412AbiC2Mmr (ORCPT ); Tue, 29 Mar 2022 08:42:47 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1741C21547E for ; Tue, 29 Mar 2022 05:40:53 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id l14-20020aa7cace000000b003f7f8e1cbbdso10941231edt.20 for ; Tue, 29 Mar 2022 05:40:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=O7QheLFrb7/gpanG0WgUH3CDvOfcWzGQKyw+meqIa2c=; b=nwdrOPNgrlRK/p217vtYWLPWJHANewfRLQpav+XSHbkAVHEnW3oP60FbQ/XxJx5Wey 8DRycD6Z8aEu0MC/3X0fisGnjf5imwmv/pW9pycKVeSdzaHTJ5Rg895wxW0ZrqOGPo10 IfXG+qAD/A/UF9Bi9etjM3pLZn0NbG7nPno2kSpwLlV8g6SDRLw6y8Wk3qoccWfMZ8be drDAk5gciM2kZ8tcU4aiCTs8FvlgiztSYF5pfb76GBFYTSFhMc7u/3/M4f77WEnkaJxj KHDu5r2kXFtX3OnAiGQmLBocYjFXf2eOhSXJmKa/Qj5ogXrOHpI3AL+qNsyyhKmK9AoV 8PsQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=O7QheLFrb7/gpanG0WgUH3CDvOfcWzGQKyw+meqIa2c=; b=fVYOF2q2RE5CiJnYCdTGK+Cw7Wt6N1hXkO4J97fND2QAscYSKPygbDOrd2gQnPQKEH 1bD30U/SwNMih5D5apudI2R8tNq4qCrEoNj2lN8cnITvdfHYRbCiwRVa/D1UlP9FkinP Pfl/m/YWDbIfPWOCu46dQKqY79QMYRjP/L4ffLbojmDo3wXZhAD2qIGZ4QE8cNE0UYxj b+88c+VFkAIwMSMnAI4N4ljST+TFtHhjOAQh7/Zq5qOqvwtSwBnuhZ0LpnzTHdr1/veM ElPJYU8EfMUzqzBpDtZxCLnvN9BJniLkOwtR8YnWUwyrSRXbwAMG7vUY8dg4Dgvy90cI 7oaA== X-Gm-Message-State: AOAM531G1CZXD11Hqy+ulTk9T6Gpr4/+ga+5uP2r6VXIMEg61aezHYAe bZLEvPKP3oAPqFm+3mG/IQQsA5ri4cw= X-Google-Smtp-Source: ABdhPJw72M5zTQlc12l/JxfWqejUITTKjW22Nisg7zg2gWpioCaXSJXtz0/OVqyNYeeR7potvImif+IfrBc= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:60cc:b0:6e0:dab3:ca76 with SMTP id hv12-20020a17090760cc00b006e0dab3ca76mr19088650ejc.154.1648557652185; Tue, 29 Mar 2022 05:40:52 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:38 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-10-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 09/48] kmsan: mark noinstr as __no_sanitize_memory From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" noinstr functions should never be instrumented, so make KMSAN skip them by applying the __no_sanitize_memory attribute. Signed-off-by: Alexander Potapenko --- v2: -- moved this patch earlier in the series per Mark Rutland's request Link: https://linux-review.googlesource.com/id/I3c9abe860b97b49bc0c8026918b= 17a50448dec0d --- include/linux/compiler_types.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 3c1795fdb5686..286675559cbba 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -221,7 +221,8 @@ struct ftrace_likely_data { /* Section for code which can't be instrumented at all */ #define noinstr \ noinline notrace __attribute((__section__(".noinstr.text"))) \ - __no_kcsan __no_sanitize_address __no_profile __no_sanitize_coverage + __no_kcsan __no_sanitize_address __no_profile __no_sanitize_coverage \ + __no_sanitize_memory =20 #endif /* __KERNEL__ */ =20 --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99E2BC433F5 for ; Tue, 29 Mar 2022 12:41:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236393AbiC2Mn1 (ORCPT ); Tue, 29 Mar 2022 08:43:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33914 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236472AbiC2Mms (ORCPT ); Tue, 29 Mar 2022 08:42:48 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 756B7216FB3 for ; Tue, 29 Mar 2022 05:40:56 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id i22-20020a508716000000b0041908045af3so10872398edb.3 for ; Tue, 29 Mar 2022 05:40:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=6/sayBfyjsH2Y3AfJUr4VjD2mcwzYPMTZLT8of1IREg=; b=gPCDqH0qCHmbSNoYXOMeBTfYfmSmbXUFr3zh1f5ZPo0Pb3cPpOC3T9Li2Ba/s3wfmz gQ2bEXLw+QpWVfUvoSRzIkAV0HGDefVdPLjvrmeyUVW1CwUFY/o/0iTuMpy00qfMhXYD S7Ny7FKu+E+vuPhMe33YJ17U98elZnTICW7Rf7enJip6PmyGcM/IKGLtw9meI2L8r4T/ 1B+1Mwp5rxGR/FQmQuUKPOmSqvjvULvO7aaLABE+y2HIRD0KCdYz/+lXqsDIyraIiLZx Zx5IqS0hdEQnvzCuaM2/3M5V3KZQK9XBZNOZyH5gNz855mbOM3DEDHGoM3IbScEoxq6l Nn2g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=6/sayBfyjsH2Y3AfJUr4VjD2mcwzYPMTZLT8of1IREg=; b=FtBMDrDBqqtM+ziKANkq+VU5MjbctZUOR4k+tQ9g/wPfREp4eiTg/cr6uNbE4pT53H om0L3Gt/5NnkGWeK1aojLHJ/ugG/EBPRwNfIBk8lDO8AXZV4Fm8gkU9bfFxqiNEL7i6h lsfThcXKKZepQoyIny9AahYxrERQZKPhTkN9P299l80AT+ReJVqAwKGEbHR0MQ8qcqyg RccSPbHLm0VXVtve0OB621XoobPcDpUxxWIRuk56bM8a7xZ8tZP3utAG+JbruF6FzAXI zSqNUZgubLanfjAZfvGFNAbIDtMNJ2e8334CVeo7m9LjEJ8sqgy/oh927shl1LAA126/ MOxA== X-Gm-Message-State: AOAM530aVIEtLtBd1DLTr81flPe6b7f8x1PbJ1edlfGiMbZjzVYRlzxP URyZ1IcyM84hhEHa9Y4rSO+aiB10oAM= X-Google-Smtp-Source: ABdhPJz19CPV3rmf1QsGMB2W43cqP02JXhPWr4JS53hrOaKJGQqZA3fyKoTvfV9B2lQS0qWbgSPFKMg0F4A= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:40da:b0:6ce:51b:a593 with SMTP id a26-20020a17090640da00b006ce051ba593mr34588142ejk.604.1648557654844; Tue, 29 Mar 2022 05:40:54 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:39 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-11-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 10/48] x86: kmsan: pgtable: reduce vmalloc space From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KMSAN is going to use 3/4 of existing vmalloc space to hold the metadata, therefore we lower VMALLOC_END to make sure vmalloc() doesn't allocate past the first 1/4. Signed-off-by: Alexander Potapenko --- v2: -- added x86: to the title Link: https://linux-review.googlesource.com/id/I9d8b7f0a88a639f1263bc693cbd= 5c136626f7efd --- arch/x86/include/asm/pgtable_64_types.h | 41 ++++++++++++++++++++++++- arch/x86/mm/init_64.c | 2 +- 2 files changed, 41 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm= /pgtable_64_types.h index 91ac106545703..7f15d43754a34 100644 --- a/arch/x86/include/asm/pgtable_64_types.h +++ b/arch/x86/include/asm/pgtable_64_types.h @@ -139,7 +139,46 @@ extern unsigned int ptrs_per_p4d; # define VMEMMAP_START __VMEMMAP_BASE_L4 #endif /* CONFIG_DYNAMIC_MEMORY_LAYOUT */ =20 -#define VMALLOC_END (VMALLOC_START + (VMALLOC_SIZE_TB << 40) - 1) +#define VMEMORY_END (VMALLOC_START + (VMALLOC_SIZE_TB << 40) - 1) + +#ifndef CONFIG_KMSAN +#define VMALLOC_END VMEMORY_END +#else +/* + * In KMSAN builds vmalloc area is four times smaller, and the remaining 3= /4 + * are used to keep the metadata for virtual pages. The memory formerly + * belonging to vmalloc area is now laid out as follows: + * + * 1st quarter: VMALLOC_START to VMALLOC_END - new vmalloc area + * 2nd quarter: KMSAN_VMALLOC_SHADOW_START to + * VMALLOC_END+KMSAN_VMALLOC_SHADOW_OFFSET - vmalloc area sha= dow + * 3rd quarter: KMSAN_VMALLOC_ORIGIN_START to + * VMALLOC_END+KMSAN_VMALLOC_ORIGIN_OFFSET - vmalloc area ori= gins + * 4th quarter: KMSAN_MODULES_SHADOW_START to KMSAN_MODULES_ORIGIN_START + * - shadow for modules, + * KMSAN_MODULES_ORIGIN_START to + * KMSAN_MODULES_ORIGIN_START + MODULES_LEN - origins for mod= ules. + */ +#define VMALLOC_QUARTER_SIZE ((VMALLOC_SIZE_TB << 40) >> 2) +#define VMALLOC_END (VMALLOC_START + VMALLOC_QUARTER_SIZE - 1) + +/* + * vmalloc metadata addresses are calculated by adding shadow/origin offse= ts + * to vmalloc address. + */ +#define KMSAN_VMALLOC_SHADOW_OFFSET VMALLOC_QUARTER_SIZE +#define KMSAN_VMALLOC_ORIGIN_OFFSET (VMALLOC_QUARTER_SIZE << 1) + +#define KMSAN_VMALLOC_SHADOW_START (VMALLOC_START + KMSAN_VMALLOC_SHADOW_O= FFSET) +#define KMSAN_VMALLOC_ORIGIN_START (VMALLOC_START + KMSAN_VMALLOC_ORIGIN_O= FFSET) + +/* + * The shadow/origin for modules are placed one by one in the last 1/4 of + * vmalloc space. + */ +#define KMSAN_MODULES_SHADOW_START (VMALLOC_END + KMSAN_VMALLOC_ORIGIN_OFF= SET + 1) +#define KMSAN_MODULES_ORIGIN_START (KMSAN_MODULES_SHADOW_START + MODULES_L= EN) +#endif /* CONFIG_KMSAN */ =20 #define MODULES_VADDR (__START_KERNEL_map + KERNEL_IMAGE_SIZE) /* The module sections ends with the start of the fixmap */ diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 96d34ebb20a9e..fcea37beb3911 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1287,7 +1287,7 @@ static void __init preallocate_vmalloc_pages(void) unsigned long addr; const char *lvl; =20 - for (addr =3D VMALLOC_START; addr <=3D VMALLOC_END; addr =3D ALIGN(addr += 1, PGDIR_SIZE)) { + for (addr =3D VMALLOC_START; addr <=3D VMEMORY_END; addr =3D ALIGN(addr += 1, PGDIR_SIZE)) { pgd_t *pgd =3D pgd_offset_k(addr); p4d_t *p4d; pud_t *pud; --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9265C4332F for ; Tue, 29 Mar 2022 12:41:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236531AbiC2Mnk (ORCPT ); Tue, 29 Mar 2022 08:43:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236516AbiC2Mmy (ORCPT ); Tue, 29 Mar 2022 08:42:54 -0400 Received: from mail-ed1-x54a.google.com (mail-ed1-x54a.google.com [IPv6:2a00:1450:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD285211ED2 for ; Tue, 29 Mar 2022 05:41:04 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id j39-20020a05640223a700b0041992453601so8687090eda.1 for ; Tue, 29 Mar 2022 05:41:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=km5owwejhlOXuN0CdtXT+rH3PwGCxkXBDIlOmz8F8mM=; b=BPBN+Gp/HybRIj+tr7lmAPtZ/gaSTg17YfV70uHe6dI4D03YCmDJ28J1xxu73jh2dk lunM+tJfRxIWWCTitc1zqeGcNO6ui2olt/ToR74zTeetb2t645zaZRfbXnEBWBeufQcz UZFI/a7dadkwv9KhIIRq4n83fNxSMacV6CuDKWLbiQmxkp72N4gUGhDLhrX/ZY/tzqb+ wwmGDuW3C5VDusIt/9kLL08QT9f400t0JOILiCvI+CWdGaKJ8/8ZTha18LD969Vanzph EmE7KmmpEFFeSjxO/yybRJOhoovSm59NPOFmQeJCjBwZk6WuGl9hl0wb88xwAHT3OeLk 9zLA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=km5owwejhlOXuN0CdtXT+rH3PwGCxkXBDIlOmz8F8mM=; b=eJD693b5qoUoNhtpy3Bw5+go/DrdVNB/H4y/x1QM8gzmBVDjKnFG4l7aMk0Rz5iChH d37sv4qj+I5QFOK63Ho4gU5GjwWGY4RVYWymITsDujSrICyefEG0giFhFUtbBrGdrMvA QRuFQBBN3cWEYsFJe0T3w8n9mkG4jDt75Aq8/JZwGxa0IPYAm0PA8nYp4kTxtGaKyGNJ +woz/YsybxEzfwMAPeoaTtcqTrqjjVELs1Uy6osShE5BdQoE090JqUVuR179V6gWxiZi WtHjG1SIGy3qipbmgCtgPU5yYUV5NRSwHPkF41N3K9+i2iCSJ+xqo/sW8BPMDr5BJb49 TuOQ== X-Gm-Message-State: AOAM5327aAmArZacX0gWgc4On4KlpL4jehrN4gn7Hv+ReSpLjm0xM10g RBJrYcHjHgSfo/iozQ91OXWHIheKCZk= X-Google-Smtp-Source: ABdhPJxTFdKgNMHXnOGxM/ndXx2ll4nIIoJnFlW5u5FSX6vDALAQ8Bv8xnOw9ZMBkOj50HuqwBsroT31ous= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a05:6402:27c7:b0:41b:51ca:f542 with SMTP id c7-20020a05640227c700b0041b51caf542mr3174378ede.149.1648557657545; Tue, 29 Mar 2022 05:40:57 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:40 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-12-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 11/48] libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KMSAN adds extra metadata fields to struct page, so it does not fit into 64 bytes anymore. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I353796acc6a850bfd7bb342aa1b= 63e616fc614f1 --- drivers/nvdimm/nd.h | 2 +- drivers/nvdimm/pfn_devs.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h index 6f8ce114032d0..b50aecd1dd423 100644 --- a/drivers/nvdimm/nd.h +++ b/drivers/nvdimm/nd.h @@ -663,7 +663,7 @@ void devm_namespace_disable(struct device *dev, struct nd_namespace_common *ndns); #if IS_ENABLED(CONFIG_ND_CLAIM) /* max struct page size independent of kernel config */ -#define MAX_STRUCT_PAGE_SIZE 64 +#define MAX_STRUCT_PAGE_SIZE 128 int nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap); #else static inline int nvdimm_setup_pfn(struct nd_pfn *nd_pfn, diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c index 58eda16f5c534..07a539195cc8b 100644 --- a/drivers/nvdimm/pfn_devs.c +++ b/drivers/nvdimm/pfn_devs.c @@ -785,7 +785,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) * when populating the vmemmap. This *should* be equal to * PMD_SIZE for most architectures. * - * Also make sure size of struct page is less than 64. We + * Also make sure size of struct page is less than 128. We * want to make sure we use large enough size here so that * we don't have a dynamic reserve space depending on * struct page size. But we also want to make sure we notice --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D37AC4332F for ; Tue, 29 Mar 2022 12:41:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236603AbiC2Mng (ORCPT ); Tue, 29 Mar 2022 08:43:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60340 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236504AbiC2Mmy (ORCPT ); Tue, 29 Mar 2022 08:42:54 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44075209A4D for ; Tue, 29 Mar 2022 05:41:03 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id v9-20020a509549000000b00418d7c2f62aso10946975eda.15 for ; Tue, 29 Mar 2022 05:41:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=cXkdgZbGJwU6k8snEczoh0k/WkFNvdUgCw+ayF9WLuQ=; b=kJ3CEmpah2i9qEH7T+C5Ga2iXnj2Y+3RwMf8YqsmELN6LOISLHU5lU3es8dFXLXr4G RwvPPr+lXFQJJVB8eC5SfjBqsSq8LtpCHYf3AswzsXu/1NhBVq2D9gsP4OH2L4CTMT4M htWXUw29Be33vwaebXorL3fSnDwOI8IYefJyHWs3/4YxoYcA+PWRfpq7JHQ6XEzLzzbD FlQgRQzQ9K3/oO1RgYlOuEtyVvqXUpOZFhIl55G6hZ3TouP4qi7NusxxsF5cTKn2krfS X+VguAz0cQlQcgvkoFLT3U0fU9ShmiXto/lOzeXy+6A0JzZKD80LdngdHu/dWikUglw0 6J5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=cXkdgZbGJwU6k8snEczoh0k/WkFNvdUgCw+ayF9WLuQ=; b=z2NZpfWnKxQ4JG9moYnC4uBGxXlzcdJ9XYvMLQ8sOpHSgg2asUPjUMI118lQ8iVXEQ vRITiMjB8OWDoxyetMyJfOfDxHpDC/yEgY2J3JmUdjfoPJNLHSq7zrh8ugayZYESmsay NQ8QQOJlfPuagYJt/0Ln+jum7P1DFFlmlnf3pyUc2D06x1Pfa/Mt2MefGIQvuNpNHj4p oVN0RynscQwH3suNV0TKB8dHm2d7LrWDBcbjKLca5Vk59NOJWqMW0F8NX+aHtCQVBHXB zxy/Y0g3KCnGz6xP0cgwrpGmzKUzKYNJlOVGMP9bLAmMAbbLYKX+a9Tit4Q8zNMb4EOl JZLw== X-Gm-Message-State: AOAM531uJnzqIFf9xWZraMkeBDqfyEF6fPeszJud25PtolocFJHqneo7 9LrEJ0PV2lwm3+4YPzeRVrVaQrRERuc= X-Google-Smtp-Source: ABdhPJywI+kpf/WbEulTkI+WWQEh96+s7tqreK3VONJIUmDgWPb5bSFILSkC6rnkhNtKnHdOQAMR0bfb/+4= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:9743:b0:6d8:632a:a42d with SMTP id o3-20020a170906974300b006d8632aa42dmr34840939ejy.157.1648557662237; Tue, 29 Mar 2022 05:41:02 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:41 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-13-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 12/48] kcsan: clang: retire CONFIG_KCSAN_KCOV_BROKEN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" kcov used to be broken prior to Clang 11, but right now that version is already the minimum required to build with KCSAN, because no prior compiler has "-tsan-distinguish-volatile=3D1". Therefore KCSAN_KCOV_BROKEN is not needed anymore. Suggested-by: Marco Elver Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Ida287421577f37de337139b5b5b= 9e977e4a6fee2 --- lib/Kconfig.kcsan | 11 ----------- 1 file changed, 11 deletions(-) diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan index 63b70b8c55519..de022445fbba5 100644 --- a/lib/Kconfig.kcsan +++ b/lib/Kconfig.kcsan @@ -10,21 +10,10 @@ config HAVE_KCSAN_COMPILER For the list of compilers that support KCSAN, please see . =20 -config KCSAN_KCOV_BROKEN - def_bool KCOV && CC_HAS_SANCOV_TRACE_PC - depends on CC_IS_CLANG - depends on !$(cc-option,-Werror=3Dunused-command-line-argument -fsanitize= =3Dthread -fsanitize-coverage=3Dtrace-pc) - help - Some versions of clang support either KCSAN and KCOV but not the - combination of the two. - See https://bugs.llvm.org/show_bug.cgi?id=3D45831 for the status - in newer releases. - menuconfig KCSAN bool "KCSAN: dynamic data race detector" depends on HAVE_ARCH_KCSAN && HAVE_KCSAN_COMPILER depends on DEBUG_KERNEL && !KASAN - depends on !KCSAN_KCOV_BROKEN select STACKTRACE help The Kernel Concurrency Sanitizer (KCSAN) is a dynamic --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 314FCC433F5 for ; Tue, 29 Mar 2022 12:42:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235794AbiC2Mnr (ORCPT ); Tue, 29 Mar 2022 08:43:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236444AbiC2Mm7 (ORCPT ); Tue, 29 Mar 2022 08:42:59 -0400 Received: from mail-ed1-x54a.google.com (mail-ed1-x54a.google.com [IPv6:2a00:1450:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ACF2D20E978 for ; Tue, 29 Mar 2022 05:41:06 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id c22-20020a50f616000000b004196649d144so10956411edn.10 for ; Tue, 29 Mar 2022 05:41:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc:content-transfer-encoding; bh=biz+rIgT55uFrE6N/OSPE++HUy2NNspyJjcc8tnQ5F0=; b=oLTFqHECxdHQo2riVa6e2vk4JMzdrRa1nobyCYGqlnhiDE0UdJp+Oi1maxK3KKIeds yrNdR+/3nItl2kUXDWqESD1KAFY7oRRLfv54KjcYGz1FAemAYnBfHY4Srr5o+6tgXhy5 03Ldzu2oqeMoT6MQqtm4NLJouUQ1R7CtmlegonxogZiS0UCbzacZjcCNuMYDT7Kl8FJr bW8ZlFrsKssY1jjdDaliFGdSPlZIiVPBlbg4STStv5Gc3GqttGj2v1lMeFAhbUdzbx5L kPr1MSXcksO1CR8KyIAYZ7gGv5T0A9REaJe/mR20u0Yevzkjxxpiw5T8I9qH/+5FqIA9 ATPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc:content-transfer-encoding; bh=biz+rIgT55uFrE6N/OSPE++HUy2NNspyJjcc8tnQ5F0=; b=CpOetV3PidK+5YNTaUsrsqFryesrdFm0q2cJZ9SN6xkm7IaCy97+uVXEKWo5THg7sg MrZGMgHtBt504bxtOgOyrctL2+sdYrHeE0m6b9jK87Xvt52LeLhz4L2yH3wl4ViQabSk 8QvgeDswNKrq7Mb91qt/efYiVBjrVM1blsSXudg1YdY39/HJXVxk+3yaXAJV9eMzmwO3 b9b1TevbEjsD9FE1VG9PxnGQe3Kb64xr357agguvcfOSBDtKTvvBovfVCCNfXJASOwLV A4sv71PPwwEwguIYrhZJ2JfnXHZ0OUCG4rpQcaOABQ+infd3lGmsh3ko9AbsZ6dQG2D7 eJUw== X-Gm-Message-State: AOAM531pLWWam5GXcAiF/D8xxzorQbeh2u9P3gZySUnsrTyCbz/eInqC bIc6y7IPhb+oJvj9WPSrj+XiDRoefw0= X-Google-Smtp-Source: ABdhPJxzkkrniU6QgqwuIr0F+dsVSYX1ecitHrX465QTJKPfG1GcAjlTfnc+Fpa5BJDcv5//XO+1tVMTk9U= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:86a8:b0:6db:6c1c:d9c4 with SMTP id qa40-20020a17090786a800b006db6c1cd9c4mr33198729ejc.640.1648557664969; Tue, 29 Mar 2022 05:41:04 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:42 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-14-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 13/48] kmsan: add KMSAN runtime core From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" For each memory location KernelMemorySanitizer maintains two types of metadata: 1. The so-called shadow of that location - =D0=B0 byte:byte mapping describ= ing whether or not individual bits of memory are initialized (shadow is 0) or not (shadow is 1). 2. The origins of that location - =D0=B0 4-byte:4-byte mapping containing 4-byte IDs of the stack traces where uninitialized values were created. Each struct page now contains pointers to two struct pages holding KMSAN metadata (shadow and origins) for the original struct page. Utility routines in mm/kmsan/core.c and mm/kmsan/shadow.c handle the metadata creation, addressing, copying and checking. mm/kmsan/report.c performs error reporting in the cases an uninitialized value is used in a way that leads to undefined behavior. KMSAN compiler instrumentation is responsible for tracking the metadata along with the kernel memory. mm/kmsan/instrumentation.c provides the implementation for instrumentation hooks that are called from files compiled with -fsanitize=3Dkernel-memory. To aid parameter passing (also done at instrumentation level), each task_struct now contains a struct kmsan_task_state used to track the metadata of function parameters and return values for that task. Finally, this patch provides CONFIG_KMSAN that enables KMSAN, and declares CFLAGS_KMSAN, which are applied to files compiled with KMSAN. The KMSAN_SANITIZE:=3Dn Makefile directive can be used to completely disable KMSAN instrumentation for certain files. Similarly, KMSAN_ENABLE_CHECKS:=3Dn disables KMSAN checks and makes newly created stack memory initialized. Users can also use functions from include/linux/kmsan-checks.h to mark certain memory regions as uninitialized or initialized (this is called "poisoning" and "unpoisoning") or check that a particular region is initialized. Signed-off-by: Alexander Potapenko --- v2: -- as requested by Greg K-H, moved hooks for different subsystems to respe= ctive patches, rewrote the patch description; -- addressed comments by Dmitry Vyukov; -- added a note about KMSAN being not intended for production use. -- fix case of unaligned dst in kmsan_internal_memmove_metadata() Link: https://linux-review.googlesource.com/id/I9b71bfe3425466c97159f9de006= 2e5e8e4fec866 --- Makefile | 1 + include/linux/kmsan-checks.h | 64 +++++ include/linux/kmsan.h | 47 ++++ include/linux/mm_types.h | 12 + include/linux/sched.h | 5 + lib/Kconfig.debug | 1 + lib/Kconfig.kmsan | 23 ++ mm/Makefile | 1 + mm/kmsan/Makefile | 18 ++ mm/kmsan/core.c | 453 +++++++++++++++++++++++++++++++++++ mm/kmsan/hooks.c | 66 +++++ mm/kmsan/instrumentation.c | 267 +++++++++++++++++++++ mm/kmsan/kmsan.h | 183 ++++++++++++++ mm/kmsan/report.c | 211 ++++++++++++++++ mm/kmsan/shadow.c | 186 ++++++++++++++ scripts/Makefile.kmsan | 1 + scripts/Makefile.lib | 9 + 17 files changed, 1548 insertions(+) create mode 100644 include/linux/kmsan-checks.h create mode 100644 include/linux/kmsan.h create mode 100644 lib/Kconfig.kmsan create mode 100644 mm/kmsan/Makefile create mode 100644 mm/kmsan/core.c create mode 100644 mm/kmsan/hooks.c create mode 100644 mm/kmsan/instrumentation.c create mode 100644 mm/kmsan/kmsan.h create mode 100644 mm/kmsan/report.c create mode 100644 mm/kmsan/shadow.c create mode 100644 scripts/Makefile.kmsan diff --git a/Makefile b/Makefile index 7214f075e1f06..251fa89068ed1 100644 --- a/Makefile +++ b/Makefile @@ -1006,6 +1006,7 @@ include-y :=3D scripts/Makefile.extrawarn include-$(CONFIG_DEBUG_INFO) +=3D scripts/Makefile.debug include-$(CONFIG_KASAN) +=3D scripts/Makefile.kasan include-$(CONFIG_KCSAN) +=3D scripts/Makefile.kcsan +include-$(CONFIG_KMSAN) +=3D scripts/Makefile.kmsan include-$(CONFIG_UBSAN) +=3D scripts/Makefile.ubsan include-$(CONFIG_KCOV) +=3D scripts/Makefile.kcov include-$(CONFIG_GCC_PLUGINS) +=3D scripts/Makefile.gcc-plugins diff --git a/include/linux/kmsan-checks.h b/include/linux/kmsan-checks.h new file mode 100644 index 0000000000000..a6522a0c28df9 --- /dev/null +++ b/include/linux/kmsan-checks.h @@ -0,0 +1,64 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * KMSAN checks to be used for one-off annotations in subsystems. + * + * Copyright (C) 2017-2022 Google LLC + * Author: Alexander Potapenko + * + */ + +#ifndef _LINUX_KMSAN_CHECKS_H +#define _LINUX_KMSAN_CHECKS_H + +#include + +#ifdef CONFIG_KMSAN + +/** + * kmsan_poison_memory() - Mark the memory range as uninitialized. + * @address: address to start with. + * @size: size of buffer to poison. + * @flags: GFP flags for allocations done by this function. + * + * Until other data is written to this range, KMSAN will treat it as + * uninitialized. Error reports for this memory will reference the call si= te of + * kmsan_poison_memory() as origin. + */ +void kmsan_poison_memory(const void *address, size_t size, gfp_t flags); + +/** + * kmsan_unpoison_memory() - Mark the memory range as initialized. + * @address: address to start with. + * @size: size of buffer to unpoison. + * + * Until other data is written to this range, KMSAN will treat it as + * initialized. + */ +void kmsan_unpoison_memory(const void *address, size_t size); + +/** + * kmsan_check_memory() - Check the memory range for being initialized. + * @address: address to start with. + * @size: size of buffer to check. + * + * If any piece of the given range is marked as uninitialized, KMSAN will = report + * an error. + */ +void kmsan_check_memory(const void *address, size_t size); + +#else + +static inline void kmsan_poison_memory(const void *address, size_t size, + gfp_t flags) +{ +} +static inline void kmsan_unpoison_memory(const void *address, size_t size) +{ +} +static inline void kmsan_check_memory(const void *address, size_t size) +{ +} + +#endif + +#endif /* _LINUX_KMSAN_CHECKS_H */ diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h new file mode 100644 index 0000000000000..4e35f43eceaa9 --- /dev/null +++ b/include/linux/kmsan.h @@ -0,0 +1,47 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * KMSAN API for subsystems. + * + * Copyright (C) 2017-2022 Google LLC + * Author: Alexander Potapenko + * + */ +#ifndef _LINUX_KMSAN_H +#define _LINUX_KMSAN_H + +#include +#include +#include +#include +#include + +struct page; + +#ifdef CONFIG_KMSAN + +/* These constants are defined in the MSan LLVM instrumentation pass. */ +#define KMSAN_RETVAL_SIZE 800 +#define KMSAN_PARAM_SIZE 800 + +struct kmsan_context_state { + char param_tls[KMSAN_PARAM_SIZE]; + char retval_tls[KMSAN_RETVAL_SIZE]; + char va_arg_tls[KMSAN_PARAM_SIZE]; + char va_arg_origin_tls[KMSAN_PARAM_SIZE]; + u64 va_arg_overflow_size_tls; + char param_origin_tls[KMSAN_PARAM_SIZE]; + depot_stack_handle_t retval_origin_tls; +}; + +#undef KMSAN_PARAM_SIZE +#undef KMSAN_RETVAL_SIZE + +struct kmsan_ctx { + struct kmsan_context_state cstate; + int kmsan_in_runtime; + bool allow_reporting; +}; + +#endif + +#endif /* _LINUX_KMSAN_H */ diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 0f549870da6a0..eace8b4ec083c 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -206,6 +206,18 @@ struct page { not kmapped, ie. highmem) */ #endif /* WANT_PAGE_VIRTUAL */ =20 +#ifdef CONFIG_KMSAN + /* + * KMSAN metadata for this page: + * - shadow page: every bit indicates whether the corresponding + * bit of the original page is initialized (0) or not (1); + * - origin page: every 4 bytes contain an id of the stack trace + * where the uninitialized value was created. + */ + struct page *kmsan_shadow; + struct page *kmsan_origin; +#endif + #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS int _last_cpupid; #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index 75ba8aa60248b..d95305372b7a1 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -1349,6 +1350,10 @@ struct task_struct { #endif #endif =20 +#ifdef CONFIG_KMSAN + struct kmsan_ctx kmsan_ctx; +#endif + #if IS_ENABLED(CONFIG_KUNIT) struct kunit *kunit_test; #endif diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 14b89aa37c5c9..d6dc915f26c76 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -968,6 +968,7 @@ config DEBUG_STACKOVERFLOW =20 source "lib/Kconfig.kasan" source "lib/Kconfig.kfence" +source "lib/Kconfig.kmsan" =20 endmenu # "Memory Debugging" =20 diff --git a/lib/Kconfig.kmsan b/lib/Kconfig.kmsan new file mode 100644 index 0000000000000..199f79d031f94 --- /dev/null +++ b/lib/Kconfig.kmsan @@ -0,0 +1,23 @@ +config HAVE_ARCH_KMSAN + bool + +config HAVE_KMSAN_COMPILER + def_bool (CC_IS_CLANG && $(cc-option,-fsanitize=3Dkernel-memory -mllvm -m= san-disable-checks=3D1)) + +config KMSAN + bool "KMSAN: detector of uninitialized values use" + depends on HAVE_ARCH_KMSAN && HAVE_KMSAN_COMPILER + depends on SLUB && DEBUG_KERNEL && !KASAN && !KCSAN + depends on CC_IS_CLANG && CLANG_VERSION >=3D 140000 + select STACKDEPOT + select STACKDEPOT_ALWAYS_INIT + help + KernelMemorySanitizer (KMSAN) is a dynamic detector of uses of + uninitialized values in the kernel. It is based on compiler + instrumentation provided by Clang and thus requires Clang to build. + + An important note is that KMSAN is not intended for production use, + because it drastically increases kernel memory footprint and slows + the whole system down. + + See for more details. diff --git a/mm/Makefile b/mm/Makefile index 70d4309c9ce33..b04d9e8c8d4e0 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -89,6 +89,7 @@ obj-$(CONFIG_SLAB) +=3D slab.o obj-$(CONFIG_SLUB) +=3D slub.o obj-$(CONFIG_KASAN) +=3D kasan/ obj-$(CONFIG_KFENCE) +=3D kfence/ +obj-$(CONFIG_KMSAN) +=3D kmsan/ obj-$(CONFIG_FAILSLAB) +=3D failslab.o obj-$(CONFIG_MEMTEST) +=3D memtest.o obj-$(CONFIG_MIGRATION) +=3D migrate.o diff --git a/mm/kmsan/Makefile b/mm/kmsan/Makefile new file mode 100644 index 0000000000000..a80dde1de7048 --- /dev/null +++ b/mm/kmsan/Makefile @@ -0,0 +1,18 @@ +obj-y :=3D core.o instrumentation.o hooks.o report.o shadow.o + +KMSAN_SANITIZE :=3D n +KCOV_INSTRUMENT :=3D n +UBSAN_SANITIZE :=3D n + +# Disable instrumentation of KMSAN runtime with other tools. +CC_FLAGS_KMSAN_RUNTIME :=3D -fno-stack-protector +CC_FLAGS_KMSAN_RUNTIME +=3D $(call cc-option,-fno-conserve-stack) +CC_FLAGS_KMSAN_RUNTIME +=3D -DDISABLE_BRANCH_PROFILING + +CFLAGS_REMOVE.o =3D $(CC_FLAGS_FTRACE) + +CFLAGS_core.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) +CFLAGS_hooks.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) +CFLAGS_instrumentation.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) +CFLAGS_report.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) +CFLAGS_shadow.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) diff --git a/mm/kmsan/core.c b/mm/kmsan/core.c new file mode 100644 index 0000000000000..f4196f274e754 --- /dev/null +++ b/mm/kmsan/core.c @@ -0,0 +1,453 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KMSAN runtime library. + * + * Copyright (C) 2017-2022 Google LLC + * Author: Alexander Potapenko + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../slab.h" +#include "kmsan.h" + +/* + * Avoid creating too long origin chains, these are unlikely to participat= e in + * real reports. + */ +#define MAX_CHAIN_DEPTH 7 +#define NUM_SKIPPED_TO_WARN 10000 + +bool kmsan_enabled __read_mostly; + +/* + * Per-CPU KMSAN context to be used in interrupts, where current->kmsan is + * unavaliable. + */ +DEFINE_PER_CPU(struct kmsan_ctx, kmsan_percpu_ctx); + +void kmsan_internal_poison_memory(void *address, size_t size, gfp_t flags, + unsigned int poison_flags) +{ + u32 extra_bits =3D + kmsan_extra_bits(/*depth*/ 0, poison_flags & KMSAN_POISON_FREE); + bool checked =3D poison_flags & KMSAN_POISON_CHECK; + depot_stack_handle_t handle; + + handle =3D kmsan_save_stack_with_flags(flags, extra_bits); + kmsan_internal_set_shadow_origin(address, size, -1, handle, checked); +} + +void kmsan_internal_unpoison_memory(void *address, size_t size, bool check= ed) +{ + kmsan_internal_set_shadow_origin(address, size, 0, 0, checked); +} + +depot_stack_handle_t kmsan_save_stack_with_flags(gfp_t flags, + unsigned int extra) +{ + unsigned long entries[KMSAN_STACK_DEPTH]; + unsigned int nr_entries; + + nr_entries =3D stack_trace_save(entries, KMSAN_STACK_DEPTH, 0); + nr_entries =3D filter_irq_stacks(entries, nr_entries); + + /* Don't sleep (see might_sleep_if() in __alloc_pages_nodemask()). */ + flags &=3D ~__GFP_DIRECT_RECLAIM; + + return __stack_depot_save(entries, nr_entries, extra, flags, true); +} + +/* Copy the metadata following the memmove() behavior. */ +void kmsan_internal_memmove_metadata(void *dst, void *src, size_t n) +{ + depot_stack_handle_t old_origin =3D 0, new_origin =3D 0; + int src_slots, dst_slots, i, iter, step, skip_bits; + depot_stack_handle_t *origin_src, *origin_dst; + void *shadow_src, *shadow_dst; + u32 *align_shadow_src, shadow; + bool backwards; + + shadow_dst =3D kmsan_get_metadata(dst, KMSAN_META_SHADOW); + if (!shadow_dst) + return; + KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(dst, n)); + + shadow_src =3D kmsan_get_metadata(src, KMSAN_META_SHADOW); + if (!shadow_src) { + /* + * |src| is untracked: zero out destination shadow, ignore the + * origins, we're done. + */ + __memset(shadow_dst, 0, n); + return; + } + KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(src, n)); + + __memmove(shadow_dst, shadow_src, n); + + origin_dst =3D kmsan_get_metadata(dst, KMSAN_META_ORIGIN); + origin_src =3D kmsan_get_metadata(src, KMSAN_META_ORIGIN); + KMSAN_WARN_ON(!origin_dst || !origin_src); + src_slots =3D (ALIGN((u64)src + n, KMSAN_ORIGIN_SIZE) - + ALIGN_DOWN((u64)src, KMSAN_ORIGIN_SIZE)) / + KMSAN_ORIGIN_SIZE; + dst_slots =3D (ALIGN((u64)dst + n, KMSAN_ORIGIN_SIZE) - + ALIGN_DOWN((u64)dst, KMSAN_ORIGIN_SIZE)) / + KMSAN_ORIGIN_SIZE; + KMSAN_WARN_ON((src_slots < 1) || (dst_slots < 1)); + KMSAN_WARN_ON((src_slots - dst_slots > 1) || + (dst_slots - src_slots < -1)); + + backwards =3D dst > src; + i =3D backwards ? min(src_slots, dst_slots) - 1 : 0; + iter =3D backwards ? -1 : 1; + + align_shadow_src =3D + (u32 *)ALIGN_DOWN((u64)shadow_src, KMSAN_ORIGIN_SIZE); + for (step =3D 0; step < min(src_slots, dst_slots); step++, i +=3D iter) { + KMSAN_WARN_ON(i < 0); + shadow =3D align_shadow_src[i]; + if (i =3D=3D 0) { + /* + * If |src| isn't aligned on KMSAN_ORIGIN_SIZE, don't + * look at the first |src % KMSAN_ORIGIN_SIZE| bytes + * of the first shadow slot. + */ + skip_bits =3D ((u64)src % KMSAN_ORIGIN_SIZE) * 8; + shadow =3D (shadow >> skip_bits) << skip_bits; + } + if (i =3D=3D src_slots - 1) { + /* + * If |src + n| isn't aligned on + * KMSAN_ORIGIN_SIZE, don't look at the last + * |(src + n) % KMSAN_ORIGIN_SIZE| bytes of the + * last shadow slot. + */ + skip_bits =3D (((u64)src + n) % KMSAN_ORIGIN_SIZE) * 8; + shadow =3D (shadow << skip_bits) >> skip_bits; + } + /* + * Overwrite the origin only if the corresponding + * shadow is nonempty. + */ + if (origin_src[i] && (origin_src[i] !=3D old_origin) && shadow) { + old_origin =3D origin_src[i]; + new_origin =3D kmsan_internal_chain_origin(old_origin); + /* + * kmsan_internal_chain_origin() may return + * NULL, but we don't want to lose the previous + * origin value. + */ + if (!new_origin) + new_origin =3D old_origin; + } + if (shadow) + origin_dst[i] =3D new_origin; + else + origin_dst[i] =3D 0; + } + /* + * If dst_slots is greater than src_slots (i.e. + * dst_slots =3D=3D src_slots + 1), there is an extra origin slot at the + * beginning or end of the destination buffer, for which we take the + * origin from the previous slot. + * This is only done if the part of the source shadow corresponding to + * slot is non-zero. + * + * E.g. if we copy 8 aligned bytes that are marked as uninitialized + * and have origins o111 and o222, to an unaligned buffer with offset 1, + * these two origins are copied to three origin slots, so one of then + * needs to be duplicated, depending on the copy direction (@backwards) + * + * src shadow: |uuuu|uuuu|....| + * src origin: |o111|o222|....| + * + * backwards =3D 0: + * dst shadow: |.uuu|uuuu|u...| + * dst origin: |....|o111|o222| - fill the empty slot with o111 + * backwards =3D 1: + * dst shadow: |.uuu|uuuu|u...| + * dst origin: |o111|o222|....| - fill the empty slot with o222 + */ + if (src_slots < dst_slots) { + if (backwards) { + shadow =3D align_shadow_src[src_slots - 1]; + skip_bits =3D (((u64)dst + n) % KMSAN_ORIGIN_SIZE) * 8; + shadow =3D (shadow << skip_bits) >> skip_bits; + if (shadow) + /* src_slots > 0, therefore dst_slots is at least 2 */ + origin_dst[dst_slots - 1] =3D origin_dst[dst_slots - 2]; + } else { + shadow =3D align_shadow_src[0]; + skip_bits =3D ((u64)dst % KMSAN_ORIGIN_SIZE) * 8; + shadow =3D (shadow >> skip_bits) << skip_bits; + if (shadow) + origin_dst[0] =3D origin_dst[1]; + } + } +} + +depot_stack_handle_t kmsan_internal_chain_origin(depot_stack_handle_t id) +{ + unsigned long entries[3]; + u32 extra_bits; + int depth; + bool uaf; + + if (!id) + return id; + /* + * Make sure we have enough spare bits in |id| to hold the UAF bit and + * the chain depth. + */ + BUILD_BUG_ON((1 << STACK_DEPOT_EXTRA_BITS) <=3D (MAX_CHAIN_DEPTH << 1)); + + extra_bits =3D stack_depot_get_extra_bits(id); + depth =3D kmsan_depth_from_eb(extra_bits); + uaf =3D kmsan_uaf_from_eb(extra_bits); + + if (depth >=3D MAX_CHAIN_DEPTH) { + static atomic_long_t kmsan_skipped_origins; + long skipped =3D atomic_long_inc_return(&kmsan_skipped_origins); + + if (skipped % NUM_SKIPPED_TO_WARN =3D=3D 0) { + pr_warn("not chained %ld origins\n", skipped); + dump_stack(); + kmsan_print_origin(id); + } + return id; + } + depth++; + extra_bits =3D kmsan_extra_bits(depth, uaf); + + entries[0] =3D KMSAN_CHAIN_MAGIC_ORIGIN; + entries[1] =3D kmsan_save_stack_with_flags(GFP_ATOMIC, 0); + entries[2] =3D id; + return __stack_depot_save(entries, ARRAY_SIZE(entries), extra_bits, + GFP_ATOMIC, true); +} + +void kmsan_internal_set_shadow_origin(void *addr, size_t size, int b, + u32 origin, bool checked) +{ + u64 address =3D (u64)addr; + void *shadow_start; + u32 *origin_start; + size_t pad =3D 0; + int i; + + KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(addr, size)); + shadow_start =3D kmsan_get_metadata(addr, KMSAN_META_SHADOW); + if (!shadow_start) { + /* + * kmsan_metadata_is_contiguous() is true, so either all shadow + * and origin pages are NULL, or all are non-NULL. + */ + if (checked) { + pr_err("%s: not memsetting %ld bytes starting at %px, because the shado= w is NULL\n", + __func__, size, addr); + BUG(); + } + return; + } + __memset(shadow_start, b, size); + + if (!IS_ALIGNED(address, KMSAN_ORIGIN_SIZE)) { + pad =3D address % KMSAN_ORIGIN_SIZE; + address -=3D pad; + size +=3D pad; + } + size =3D ALIGN(size, KMSAN_ORIGIN_SIZE); + origin_start =3D + (u32 *)kmsan_get_metadata((void *)address, KMSAN_META_ORIGIN); + + for (i =3D 0; i < size / KMSAN_ORIGIN_SIZE; i++) + origin_start[i] =3D origin; +} + +struct page *kmsan_vmalloc_to_page_or_null(void *vaddr) +{ + struct page *page; + + if (!kmsan_internal_is_vmalloc_addr(vaddr) && + !kmsan_internal_is_module_addr(vaddr)) + return NULL; + page =3D vmalloc_to_page(vaddr); + if (pfn_valid(page_to_pfn(page))) + return page; + else + return NULL; +} + +void kmsan_internal_check_memory(void *addr, size_t size, const void *user= _addr, + int reason) +{ + depot_stack_handle_t cur_origin =3D 0, new_origin =3D 0; + unsigned long addr64 =3D (unsigned long)addr; + depot_stack_handle_t *origin =3D NULL; + unsigned char *shadow =3D NULL; + int cur_off_start =3D -1; + int i, chunk_size; + size_t pos =3D 0; + + if (!size) + return; + KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(addr, size)); + while (pos < size) { + chunk_size =3D min(size - pos, + PAGE_SIZE - ((addr64 + pos) % PAGE_SIZE)); + shadow =3D kmsan_get_metadata((void *)(addr64 + pos), + KMSAN_META_SHADOW); + if (!shadow) { + /* + * This page is untracked. If there were uninitialized + * bytes before, report them. + */ + if (cur_origin) { + kmsan_enter_runtime(); + kmsan_report(cur_origin, addr, size, + cur_off_start, pos - 1, user_addr, + reason); + kmsan_leave_runtime(); + } + cur_origin =3D 0; + cur_off_start =3D -1; + pos +=3D chunk_size; + continue; + } + for (i =3D 0; i < chunk_size; i++) { + if (!shadow[i]) { + /* + * This byte is unpoisoned. If there were + * poisoned bytes before, report them. + */ + if (cur_origin) { + kmsan_enter_runtime(); + kmsan_report(cur_origin, addr, size, + cur_off_start, pos + i - 1, + user_addr, reason); + kmsan_leave_runtime(); + } + cur_origin =3D 0; + cur_off_start =3D -1; + continue; + } + origin =3D kmsan_get_metadata((void *)(addr64 + pos + i), + KMSAN_META_ORIGIN); + KMSAN_WARN_ON(!origin); + new_origin =3D *origin; + /* + * Encountered new origin - report the previous + * uninitialized range. + */ + if (cur_origin !=3D new_origin) { + if (cur_origin) { + kmsan_enter_runtime(); + kmsan_report(cur_origin, addr, size, + cur_off_start, pos + i - 1, + user_addr, reason); + kmsan_leave_runtime(); + } + cur_origin =3D new_origin; + cur_off_start =3D pos + i; + } + } + pos +=3D chunk_size; + } + KMSAN_WARN_ON(pos !=3D size); + if (cur_origin) { + kmsan_enter_runtime(); + kmsan_report(cur_origin, addr, size, cur_off_start, pos - 1, + user_addr, reason); + kmsan_leave_runtime(); + } +} + +bool kmsan_metadata_is_contiguous(void *addr, size_t size) +{ + char *cur_shadow =3D NULL, *next_shadow =3D NULL, *cur_origin =3D NULL, + *next_origin =3D NULL; + u64 cur_addr =3D (u64)addr, next_addr =3D cur_addr + PAGE_SIZE; + depot_stack_handle_t *origin_p; + bool all_untracked =3D false; + + if (!size) + return true; + + /* The whole range belongs to the same page. */ + if (ALIGN_DOWN(cur_addr + size - 1, PAGE_SIZE) =3D=3D + ALIGN_DOWN(cur_addr, PAGE_SIZE)) + return true; + + cur_shadow =3D kmsan_get_metadata((void *)cur_addr, /*is_origin*/ false); + if (!cur_shadow) + all_untracked =3D true; + cur_origin =3D kmsan_get_metadata((void *)cur_addr, /*is_origin*/ true); + if (all_untracked && cur_origin) + goto report; + + for (; next_addr < (u64)addr + size; + cur_addr =3D next_addr, cur_shadow =3D next_shadow, + cur_origin =3D next_origin, next_addr +=3D PAGE_SIZE) { + next_shadow =3D kmsan_get_metadata((void *)next_addr, false); + next_origin =3D kmsan_get_metadata((void *)next_addr, true); + if (all_untracked) { + if (next_shadow || next_origin) + goto report; + if (!next_shadow && !next_origin) + continue; + } + if (((u64)cur_shadow =3D=3D ((u64)next_shadow - PAGE_SIZE)) && + ((u64)cur_origin =3D=3D ((u64)next_origin - PAGE_SIZE))) + continue; + goto report; + } + return true; + +report: + pr_err("%s: attempting to access two shadow page ranges.\n", __func__); + pr_err("Access of size %ld at %px.\n", size, addr); + pr_err("Addresses belonging to different ranges: %px and %px\n", + (void *)cur_addr, (void *)next_addr); + pr_err("page[0].shadow: %px, page[1].shadow: %px\n", cur_shadow, + next_shadow); + pr_err("page[0].origin: %px, page[1].origin: %px\n", cur_origin, + next_origin); + origin_p =3D kmsan_get_metadata(addr, KMSAN_META_ORIGIN); + if (origin_p) { + pr_err("Origin: %08x\n", *origin_p); + kmsan_print_origin(*origin_p); + } else { + pr_err("Origin: unavailable\n"); + } + return false; +} + +bool kmsan_internal_is_module_addr(void *vaddr) +{ + return ((u64)vaddr >=3D MODULES_VADDR) && ((u64)vaddr < MODULES_END); +} + +bool kmsan_internal_is_vmalloc_addr(void *addr) +{ + return ((u64)addr >=3D VMALLOC_START) && ((u64)addr < VMALLOC_END); +} diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c new file mode 100644 index 0000000000000..4ac62fa67a02a --- /dev/null +++ b/mm/kmsan/hooks.c @@ -0,0 +1,66 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KMSAN hooks for kernel subsystems. + * + * These functions handle creation of KMSAN metadata for memory allocation= s. + * + * Copyright (C) 2018-2022 Google LLC + * Author: Alexander Potapenko + * + */ + +#include +#include +#include +#include +#include +#include + +#include "../internal.h" +#include "../slab.h" +#include "kmsan.h" + +/* + * Instrumented functions shouldn't be called under + * kmsan_enter_runtime()/kmsan_leave_runtime(), because this will lead to + * skipping effects of functions like memset() inside instrumented code. + */ + +/* Functions from kmsan-checks.h follow. */ +void kmsan_poison_memory(const void *address, size_t size, gfp_t flags) +{ + if (!kmsan_enabled || kmsan_in_runtime()) + return; + kmsan_enter_runtime(); + /* The users may want to poison/unpoison random memory. */ + kmsan_internal_poison_memory((void *)address, size, flags, + KMSAN_POISON_NOCHECK); + kmsan_leave_runtime(); +} +EXPORT_SYMBOL(kmsan_poison_memory); + +void kmsan_unpoison_memory(const void *address, size_t size) +{ + unsigned long ua_flags; + + if (!kmsan_enabled || kmsan_in_runtime()) + return; + + ua_flags =3D user_access_save(); + kmsan_enter_runtime(); + /* The users may want to poison/unpoison random memory. */ + kmsan_internal_unpoison_memory((void *)address, size, + KMSAN_POISON_NOCHECK); + kmsan_leave_runtime(); + user_access_restore(ua_flags); +} +EXPORT_SYMBOL(kmsan_unpoison_memory); + +void kmsan_check_memory(const void *addr, size_t size) +{ + if (!kmsan_enabled) + return; + return kmsan_internal_check_memory((void *)addr, size, /*user_addr*/ 0, + REASON_ANY); +} +EXPORT_SYMBOL(kmsan_check_memory); diff --git a/mm/kmsan/instrumentation.c b/mm/kmsan/instrumentation.c new file mode 100644 index 0000000000000..fe062d123a76f --- /dev/null +++ b/mm/kmsan/instrumentation.c @@ -0,0 +1,267 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KMSAN compiler API. + * + * This file implements __msan_XXX hooks that Clang inserts into the code + * compiled with -fsanitize=3Dkernel-memory. + * See Documentation/dev-tools/kmsan.rst for more information on how KMSAN + * instrumentation works. + * + * Copyright (C) 2017-2022 Google LLC + * Author: Alexander Potapenko + * + */ + +#include "kmsan.h" +#include +#include +#include + +static inline bool is_bad_asm_addr(void *addr, uintptr_t size, bool is_sto= re) +{ + if ((u64)addr < TASK_SIZE) + return true; + if (!kmsan_get_metadata(addr, KMSAN_META_SHADOW)) + return true; + return false; +} + +static inline struct shadow_origin_ptr +get_shadow_origin_ptr(void *addr, u64 size, bool store) +{ + unsigned long ua_flags =3D user_access_save(); + struct shadow_origin_ptr ret; + + ret =3D kmsan_get_shadow_origin_ptr(addr, size, store); + user_access_restore(ua_flags); + return ret; +} + +/* Get shadow and origin pointers for a memory load with non-standard size= . */ +struct shadow_origin_ptr __msan_metadata_ptr_for_load_n(void *addr, + uintptr_t size) +{ + return get_shadow_origin_ptr(addr, size, /*store*/ false); +} +EXPORT_SYMBOL(__msan_metadata_ptr_for_load_n); + +/* Get shadow and origin pointers for a memory store with non-standard siz= e. */ +struct shadow_origin_ptr __msan_metadata_ptr_for_store_n(void *addr, + uintptr_t size) +{ + return get_shadow_origin_ptr(addr, size, /*store*/ true); +} +EXPORT_SYMBOL(__msan_metadata_ptr_for_store_n); + +/* + * Declare functions that obtain shadow/origin pointers for loads and stor= es + * with fixed size. + */ +#define DECLARE_METADATA_PTR_GETTER(size) = \ + struct shadow_origin_ptr __msan_metadata_ptr_for_load_##size( \ + void *addr) \ + { \ + return get_shadow_origin_ptr(addr, size, /*store*/ false); \ + } \ + EXPORT_SYMBOL(__msan_metadata_ptr_for_load_##size); \ + struct shadow_origin_ptr __msan_metadata_ptr_for_store_##size( \ + void *addr) \ + { \ + return get_shadow_origin_ptr(addr, size, /*store*/ true); \ + } \ + EXPORT_SYMBOL(__msan_metadata_ptr_for_store_##size) + +DECLARE_METADATA_PTR_GETTER(1); +DECLARE_METADATA_PTR_GETTER(2); +DECLARE_METADATA_PTR_GETTER(4); +DECLARE_METADATA_PTR_GETTER(8); + +/* + * Handle a memory store performed by inline assembly. KMSAN conservatively + * attempts to unpoison the outputs of asm() directives to prevent false + * positives caused by missed stores. + */ +void __msan_instrument_asm_store(void *addr, uintptr_t size) +{ + unsigned long ua_flags; + + if (!kmsan_enabled || kmsan_in_runtime()) + return; + + ua_flags =3D user_access_save(); + /* + * Most of the accesses are below 32 bytes. The two exceptions so far + * are clwb() (64 bytes) and FPU state (512 bytes). + * It's unlikely that the assembly will touch more than 512 bytes. + */ + if (size > 512) { + WARN_ONCE(1, "assembly store size too big: %ld\n", size); + size =3D 8; + } + if (is_bad_asm_addr(addr, size, /*is_store*/ true)) { + user_access_restore(ua_flags); + return; + } + kmsan_enter_runtime(); + /* Unpoisoning the memory on best effort. */ + kmsan_internal_unpoison_memory(addr, size, /*checked*/ false); + kmsan_leave_runtime(); + user_access_restore(ua_flags); +} +EXPORT_SYMBOL(__msan_instrument_asm_store); + +/* Handle llvm.memmove intrinsic. */ +void *__msan_memmove(void *dst, const void *src, uintptr_t n) +{ + void *result; + + result =3D __memmove(dst, src, n); + if (!n) + /* Some people call memmove() with zero length. */ + return result; + if (!kmsan_enabled || kmsan_in_runtime()) + return result; + + kmsan_internal_memmove_metadata(dst, (void *)src, n); + + return result; +} +EXPORT_SYMBOL(__msan_memmove); + +/* Handle llvm.memcpy intrinsic. */ +void *__msan_memcpy(void *dst, const void *src, uintptr_t n) +{ + void *result; + + result =3D __memcpy(dst, src, n); + if (!n) + /* Some people call memcpy() with zero length. */ + return result; + + if (!kmsan_enabled || kmsan_in_runtime()) + return result; + + /* Using memmove instead of memcpy doesn't affect correctness. */ + kmsan_internal_memmove_metadata(dst, (void *)src, n); + + return result; +} +EXPORT_SYMBOL(__msan_memcpy); + +/* Handle llvm.memset intrinsic. */ +void *__msan_memset(void *dst, int c, uintptr_t n) +{ + void *result; + + result =3D __memset(dst, c, n); + if (!kmsan_enabled || kmsan_in_runtime()) + return result; + + kmsan_enter_runtime(); + /* + * Clang doesn't pass parameter metadata here, so it is impossible to + * use shadow of @c to set up the shadow for @dst. + */ + kmsan_internal_unpoison_memory(dst, n, /*checked*/ false); + kmsan_leave_runtime(); + + return result; +} +EXPORT_SYMBOL(__msan_memset); + +/* + * Create a new origin from an old one. This is done when storing an + * uninitialized value to memory. When reporting an error, KMSAN unrolls a= nd + * prints the whole chain of stores that preceded the use of this value. + */ +depot_stack_handle_t __msan_chain_origin(depot_stack_handle_t origin) +{ + depot_stack_handle_t ret =3D 0; + unsigned long ua_flags; + + if (!kmsan_enabled || kmsan_in_runtime()) + return ret; + + ua_flags =3D user_access_save(); + + /* Creating new origins may allocate memory. */ + kmsan_enter_runtime(); + ret =3D kmsan_internal_chain_origin(origin); + kmsan_leave_runtime(); + user_access_restore(ua_flags); + return ret; +} +EXPORT_SYMBOL(__msan_chain_origin); + +/* Poison a local variable when entering a function. */ +void __msan_poison_alloca(void *address, uintptr_t size, char *descr) +{ + depot_stack_handle_t handle; + unsigned long entries[4]; + unsigned long ua_flags; + + if (!kmsan_enabled || kmsan_in_runtime()) + return; + + ua_flags =3D user_access_save(); + entries[0] =3D KMSAN_ALLOCA_MAGIC_ORIGIN; + entries[1] =3D (u64)descr; + entries[2] =3D (u64)__builtin_return_address(0); + /* + * With frame pointers enabled, it is possible to quickly fetch the + * second frame of the caller stack without calling the unwinder. + * Without them, simply do not bother. + */ + if (IS_ENABLED(CONFIG_UNWINDER_FRAME_POINTER)) + entries[3] =3D (u64)__builtin_return_address(1); + else + entries[3] =3D 0; + + /* stack_depot_save() may allocate memory. */ + kmsan_enter_runtime(); + handle =3D stack_depot_save(entries, ARRAY_SIZE(entries), GFP_ATOMIC); + kmsan_leave_runtime(); + + kmsan_internal_set_shadow_origin(address, size, -1, handle, + /*checked*/ true); + user_access_restore(ua_flags); +} +EXPORT_SYMBOL(__msan_poison_alloca); + +/* Unpoison a local variable. */ +void __msan_unpoison_alloca(void *address, uintptr_t size) +{ + if (!kmsan_enabled || kmsan_in_runtime()) + return; + + kmsan_enter_runtime(); + kmsan_internal_unpoison_memory(address, size, /*checked*/ true); + kmsan_leave_runtime(); +} +EXPORT_SYMBOL(__msan_unpoison_alloca); + +/* + * Report that an uninitialized value with the given origin was used in a = way + * that constituted undefined behavior. + */ +void __msan_warning(u32 origin) +{ + if (!kmsan_enabled || kmsan_in_runtime()) + return; + kmsan_enter_runtime(); + kmsan_report(origin, /*address*/ 0, /*size*/ 0, + /*off_first*/ 0, /*off_last*/ 0, /*user_addr*/ 0, + REASON_ANY); + kmsan_leave_runtime(); +} +EXPORT_SYMBOL(__msan_warning); + +/* + * At the beginning of an instrumented function, obtain the pointer to + * `struct kmsan_context_state` holding the metadata for function paramete= rs. + */ +struct kmsan_context_state *__msan_get_context_state(void) +{ + return &kmsan_get_context()->cstate; +} +EXPORT_SYMBOL(__msan_get_context_state); diff --git a/mm/kmsan/kmsan.h b/mm/kmsan/kmsan.h new file mode 100644 index 0000000000000..bfe38789950a6 --- /dev/null +++ b/mm/kmsan/kmsan.h @@ -0,0 +1,183 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Functions used by the KMSAN runtime. + * + * Copyright (C) 2017-2022 Google LLC + * Author: Alexander Potapenko + * + */ + +#ifndef __MM_KMSAN_KMSAN_H +#define __MM_KMSAN_KMSAN_H + +#include +#include +#include +#include +#include +#include +#include +#include + +#define KMSAN_ALLOCA_MAGIC_ORIGIN 0xabcd0100 +#define KMSAN_CHAIN_MAGIC_ORIGIN 0xabcd0200 + +#define KMSAN_POISON_NOCHECK 0x0 +#define KMSAN_POISON_CHECK 0x1 +#define KMSAN_POISON_FREE 0x2 + +#define KMSAN_ORIGIN_SIZE 4 + +#define KMSAN_STACK_DEPTH 64 + +#define KMSAN_META_SHADOW (false) +#define KMSAN_META_ORIGIN (true) + +extern bool kmsan_enabled; +extern int panic_on_kmsan; + +/* + * KMSAN performs a lot of consistency checks that are currently enabled by + * default. BUG_ON is normally discouraged in the kernel, unless used for + * debugging, but KMSAN itself is a debugging tool, so it makes little sen= se to + * recover if something goes wrong. + */ +#define KMSAN_WARN_ON(cond) = \ + ({ \ + const bool __cond =3D WARN_ON(cond); \ + if (unlikely(__cond)) { \ + WRITE_ONCE(kmsan_enabled, false); \ + if (panic_on_kmsan) { \ + /* Can't call panic() here because */ \ + /* of uaccess checks.*/ \ + BUG(); \ + } \ + } \ + __cond; \ + }) + +/* + * A pair of metadata pointers to be returned by the instrumentation funct= ions. + */ +struct shadow_origin_ptr { + void *shadow, *origin; +}; + +struct shadow_origin_ptr kmsan_get_shadow_origin_ptr(void *addr, u64 size, + bool store); +void *kmsan_get_metadata(void *addr, bool is_origin); + +enum kmsan_bug_reason { + REASON_ANY, + REASON_COPY_TO_USER, + REASON_SUBMIT_URB, +}; + +void kmsan_print_origin(depot_stack_handle_t origin); + +/** + * kmsan_report() - Report a use of uninitialized value. + * @origin: Stack ID of the uninitialized value. + * @address: Address at which the memory access happens. + * @size: Memory access size. + * @off_first: Offset (from @address) of the first byte to be reported. + * @off_last: Offset (from @address) of the last byte to be reported. + * @user_addr: When non-NULL, denotes the userspace address to which the k= ernel + * is leaking data. + * @reason: Error type from enum kmsan_bug_reason. + * + * kmsan_report() prints an error message for a consequent group of bytes + * sharing the same origin. If an uninitialized value is used in a compari= son, + * this function is called once without specifying the addresses. When che= cking + * a memory range, KMSAN may call kmsan_report() multiple times with the s= ame + * @address, @size, @user_addr and @reason, but different @off_first and + * @off_last corresponding to different @origin values. + */ +void kmsan_report(depot_stack_handle_t origin, void *address, int size, + int off_first, int off_last, const void *user_addr, + enum kmsan_bug_reason reason); + +DECLARE_PER_CPU(struct kmsan_ctx, kmsan_percpu_ctx); + +static __always_inline struct kmsan_ctx *kmsan_get_context(void) +{ + return in_task() ? ¤t->kmsan_ctx : raw_cpu_ptr(&kmsan_percpu_ctx); +} + +/* + * When a compiler hook is invoked, it may make a call to instrumented code + * and eventually call itself recursively. To avoid that, we protect the + * runtime entry points with kmsan_enter_runtime()/kmsan_leave_runtime() a= nd + * exit the hook if kmsan_in_runtime() is true. + */ + +static __always_inline bool kmsan_in_runtime(void) +{ + if ((hardirq_count() >> HARDIRQ_SHIFT) > 1) + return true; + return kmsan_get_context()->kmsan_in_runtime; +} + +static __always_inline void kmsan_enter_runtime(void) +{ + struct kmsan_ctx *ctx; + + ctx =3D kmsan_get_context(); + KMSAN_WARN_ON(ctx->kmsan_in_runtime++); +} + +static __always_inline void kmsan_leave_runtime(void) +{ + struct kmsan_ctx *ctx =3D kmsan_get_context(); + + KMSAN_WARN_ON(--ctx->kmsan_in_runtime); +} + +depot_stack_handle_t kmsan_save_stack(void); +depot_stack_handle_t kmsan_save_stack_with_flags(gfp_t flags, + unsigned int extra_bits); + +/* + * Pack and unpack the origin chain depth and UAF flag to/from the extra b= its + * provided by the stack depot. + * The UAF flag is stored in the lowest bit, followed by the depth in the = upper + * bits. + * set_dsh_extra_bits() is responsible for clamping the value. + */ +static __always_inline unsigned int kmsan_extra_bits(unsigned int depth, + bool uaf) +{ + return (depth << 1) | uaf; +} + +static __always_inline bool kmsan_uaf_from_eb(unsigned int extra_bits) +{ + return extra_bits & 1; +} + +static __always_inline unsigned int kmsan_depth_from_eb(unsigned int extra= _bits) +{ + return extra_bits >> 1; +} + +/* + * kmsan_internal_ functions are supposed to be very simple and not requir= e the + * kmsan_in_runtime() checks. + */ +void kmsan_internal_memmove_metadata(void *dst, void *src, size_t n); +void kmsan_internal_poison_memory(void *address, size_t size, gfp_t flags, + unsigned int poison_flags); +void kmsan_internal_unpoison_memory(void *address, size_t size, bool check= ed); +void kmsan_internal_set_shadow_origin(void *address, size_t size, int b, + u32 origin, bool checked); +depot_stack_handle_t kmsan_internal_chain_origin(depot_stack_handle_t id); + +bool kmsan_metadata_is_contiguous(void *addr, size_t size); +void kmsan_internal_check_memory(void *addr, size_t size, const void *user= _addr, + int reason); +bool kmsan_internal_is_module_addr(void *vaddr); +bool kmsan_internal_is_vmalloc_addr(void *addr); + +struct page *kmsan_vmalloc_to_page_or_null(void *vaddr); + +#endif /* __MM_KMSAN_KMSAN_H */ diff --git a/mm/kmsan/report.c b/mm/kmsan/report.c new file mode 100644 index 0000000000000..59c9e7b979423 --- /dev/null +++ b/mm/kmsan/report.c @@ -0,0 +1,211 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KMSAN error reporting routines. + * + * Copyright (C) 2019-2022 Google LLC + * Author: Alexander Potapenko + * + */ + +#include +#include +#include +#include +#include + +#include "kmsan.h" + +static DEFINE_SPINLOCK(kmsan_report_lock); +#define DESCR_SIZE 128 +/* Protected by kmsan_report_lock */ +static char report_local_descr[DESCR_SIZE]; +int panic_on_kmsan __read_mostly; + +#ifdef MODULE_PARAM_PREFIX +#undef MODULE_PARAM_PREFIX +#endif +#define MODULE_PARAM_PREFIX "kmsan." +module_param_named(panic, panic_on_kmsan, int, 0); + +/* + * Skip internal KMSAN frames. + */ +static int get_stack_skipnr(const unsigned long stack_entries[], + int num_entries) +{ + int len, skip; + char buf[64]; + + for (skip =3D 0; skip < num_entries; ++skip) { + len =3D scnprintf(buf, sizeof(buf), "%ps", + (void *)stack_entries[skip]); + + /* Never show __msan_* or kmsan_* functions. */ + if ((strnstr(buf, "__msan_", len) =3D=3D buf) || + (strnstr(buf, "kmsan_", len) =3D=3D buf)) + continue; + + /* + * No match for runtime functions -- @skip entries to skip to + * get to first frame of interest. + */ + break; + } + + return skip; +} + +/* + * Currently the descriptions of locals generated by Clang look as follows: + * ----local_name@function_name + * We want to print only the name of the local, as other information in th= at + * description can be confusing. + * The meaningful part of the description is copied to a global buffer to = avoid + * allocating memory. + */ +static char *pretty_descr(char *descr) +{ + int i, pos =3D 0, len =3D strlen(descr); + + for (i =3D 0; i < len; i++) { + if (descr[i] =3D=3D '@') + break; + if (descr[i] =3D=3D '-') + continue; + report_local_descr[pos] =3D descr[i]; + if (pos + 1 =3D=3D DESCR_SIZE) + break; + pos++; + } + report_local_descr[pos] =3D 0; + return report_local_descr; +} + +void kmsan_print_origin(depot_stack_handle_t origin) +{ + unsigned long *entries =3D NULL, *chained_entries =3D NULL; + unsigned int nr_entries, chained_nr_entries, skipnr; + void *pc1 =3D NULL, *pc2 =3D NULL; + depot_stack_handle_t head; + unsigned long magic; + char *descr =3D NULL; + + if (!origin) + return; + + while (true) { + nr_entries =3D stack_depot_fetch(origin, &entries); + magic =3D nr_entries ? entries[0] : 0; + if ((nr_entries =3D=3D 4) && (magic =3D=3D KMSAN_ALLOCA_MAGIC_ORIGIN)) { + descr =3D (char *)entries[1]; + pc1 =3D (void *)entries[2]; + pc2 =3D (void *)entries[3]; + pr_err("Local variable %s created at:\n", + pretty_descr(descr)); + if (pc1) + pr_err(" %pS\n", pc1); + if (pc2) + pr_err(" %pS\n", pc2); + break; + } + if ((nr_entries =3D=3D 3) && (magic =3D=3D KMSAN_CHAIN_MAGIC_ORIGIN)) { + head =3D entries[1]; + origin =3D entries[2]; + pr_err("Uninit was stored to memory at:\n"); + chained_nr_entries =3D + stack_depot_fetch(head, &chained_entries); + kmsan_internal_unpoison_memory( + chained_entries, + chained_nr_entries * sizeof(*chained_entries), + /*checked*/ false); + skipnr =3D get_stack_skipnr(chained_entries, + chained_nr_entries); + stack_trace_print(chained_entries + skipnr, + chained_nr_entries - skipnr, 0); + pr_err("\n"); + continue; + } + pr_err("Uninit was created at:\n"); + if (nr_entries) { + skipnr =3D get_stack_skipnr(entries, nr_entries); + stack_trace_print(entries + skipnr, nr_entries - skipnr, + 0); + } else { + pr_err("(stack is not available)\n"); + } + break; + } +} + +void kmsan_report(depot_stack_handle_t origin, void *address, int size, + int off_first, int off_last, const void *user_addr, + enum kmsan_bug_reason reason) +{ + unsigned long stack_entries[KMSAN_STACK_DEPTH]; + int num_stack_entries, skipnr; + char *bug_type =3D NULL; + unsigned long flags, ua_flags; + bool is_uaf; + + if (!kmsan_enabled) + return; + if (!current->kmsan_ctx.allow_reporting) + return; + if (!origin) + return; + + current->kmsan_ctx.allow_reporting =3D false; + ua_flags =3D user_access_save(); + spin_lock_irqsave(&kmsan_report_lock, flags); + pr_err("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D\n"); + is_uaf =3D kmsan_uaf_from_eb(stack_depot_get_extra_bits(origin)); + switch (reason) { + case REASON_ANY: + bug_type =3D is_uaf ? "use-after-free" : "uninit-value"; + break; + case REASON_COPY_TO_USER: + bug_type =3D is_uaf ? "kernel-infoleak-after-free" : + "kernel-infoleak"; + break; + case REASON_SUBMIT_URB: + bug_type =3D is_uaf ? "kernel-usb-infoleak-after-free" : + "kernel-usb-infoleak"; + break; + } + + num_stack_entries =3D + stack_trace_save(stack_entries, KMSAN_STACK_DEPTH, 1); + skipnr =3D get_stack_skipnr(stack_entries, num_stack_entries); + + pr_err("BUG: KMSAN: %s in %pS\n", + bug_type, (void *)stack_entries[skipnr]); + stack_trace_print(stack_entries + skipnr, num_stack_entries - skipnr, + 0); + pr_err("\n"); + + kmsan_print_origin(origin); + + if (size) { + pr_err("\n"); + if (off_first =3D=3D off_last) + pr_err("Byte %d of %d is uninitialized\n", off_first, + size); + else + pr_err("Bytes %d-%d of %d are uninitialized\n", + off_first, off_last, size); + } + if (address) + pr_err("Memory access of size %d starts at %px\n", size, + address); + if (user_addr && reason =3D=3D REASON_COPY_TO_USER) + pr_err("Data copied to user address %px\n", user_addr); + pr_err("\n"); + dump_stack_print_info(KERN_ERR); + pr_err("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D\n"); + add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); + spin_unlock_irqrestore(&kmsan_report_lock, flags); + if (panic_on_kmsan) + panic("kmsan.panic set ...\n"); + user_access_restore(ua_flags); + current->kmsan_ctx.allow_reporting =3D true; +} diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c new file mode 100644 index 0000000000000..de58cfbc55b9d --- /dev/null +++ b/mm/kmsan/shadow.c @@ -0,0 +1,186 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KMSAN shadow implementation. + * + * Copyright (C) 2017-2022 Google LLC + * Author: Alexander Potapenko + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../internal.h" +#include "kmsan.h" + +#define shadow_page_for(page) ((page)->kmsan_shadow) + +#define origin_page_for(page) ((page)->kmsan_origin) + +static void *shadow_ptr_for(struct page *page) +{ + return page_address(shadow_page_for(page)); +} + +static void *origin_ptr_for(struct page *page) +{ + return page_address(origin_page_for(page)); +} + +static bool page_has_metadata(struct page *page) +{ + return shadow_page_for(page) && origin_page_for(page); +} + +static void set_no_shadow_origin_page(struct page *page) +{ + shadow_page_for(page) =3D NULL; + origin_page_for(page) =3D NULL; +} + +/* + * Dummy load and store pages to be used when the real metadata is unavail= able. + * There are separate pages for loads and stores, so that every load retur= ns a + * zero, and every store doesn't affect other loads. + */ +static char dummy_load_page[PAGE_SIZE] __aligned(PAGE_SIZE); +static char dummy_store_page[PAGE_SIZE] __aligned(PAGE_SIZE); + +/* + * Taken from arch/x86/mm/physaddr.h to avoid using an instrumented versio= n. + */ +static int kmsan_phys_addr_valid(unsigned long addr) +{ + if (IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT)) + return !(addr >> boot_cpu_data.x86_phys_bits); + else + return 1; +} + +/* + * Taken from arch/x86/mm/physaddr.c to avoid using an instrumented versio= n. + */ +static bool kmsan_virt_addr_valid(void *addr) +{ + unsigned long x =3D (unsigned long)addr; + unsigned long y =3D x - __START_KERNEL_map; + + /* use the carry flag to determine if x was < __START_KERNEL_map */ + if (unlikely(x > y)) { + x =3D y + phys_base; + + if (y >=3D KERNEL_IMAGE_SIZE) + return false; + } else { + x =3D y + (__START_KERNEL_map - PAGE_OFFSET); + + /* carry flag will be set if starting x was >=3D PAGE_OFFSET */ + if ((x > y) || !kmsan_phys_addr_valid(x)) + return false; + } + + return pfn_valid(x >> PAGE_SHIFT); +} + +static unsigned long vmalloc_meta(void *addr, bool is_origin) +{ + unsigned long addr64 =3D (unsigned long)addr, off; + + KMSAN_WARN_ON(is_origin && !IS_ALIGNED(addr64, KMSAN_ORIGIN_SIZE)); + if (kmsan_internal_is_vmalloc_addr(addr)) { + off =3D addr64 - VMALLOC_START; + return off + (is_origin ? KMSAN_VMALLOC_ORIGIN_START : + KMSAN_VMALLOC_SHADOW_START); + } + if (kmsan_internal_is_module_addr(addr)) { + off =3D addr64 - MODULES_VADDR; + return off + (is_origin ? KMSAN_MODULES_ORIGIN_START : + KMSAN_MODULES_SHADOW_START); + } + return 0; +} + +static struct page *virt_to_page_or_null(void *vaddr) +{ + if (kmsan_virt_addr_valid(vaddr)) + return virt_to_page(vaddr); + else + return NULL; +} + +struct shadow_origin_ptr kmsan_get_shadow_origin_ptr(void *address, u64 si= ze, + bool store) +{ + struct shadow_origin_ptr ret; + void *shadow; + + /* + * Even if we redirect this memory access to the dummy page, it will + * go out of bounds. + */ + KMSAN_WARN_ON(size > PAGE_SIZE); + + if (!kmsan_enabled || kmsan_in_runtime()) + goto return_dummy; + + KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(address, size)); + shadow =3D kmsan_get_metadata(address, KMSAN_META_SHADOW); + if (!shadow) + goto return_dummy; + + ret.shadow =3D shadow; + ret.origin =3D kmsan_get_metadata(address, KMSAN_META_ORIGIN); + return ret; + +return_dummy: + if (store) { + /* Ignore this store. */ + ret.shadow =3D dummy_store_page; + ret.origin =3D dummy_store_page; + } else { + /* This load will return zero. */ + ret.shadow =3D dummy_load_page; + ret.origin =3D dummy_load_page; + } + return ret; +} + +/* + * Obtain the shadow or origin pointer for the given address, or NULL if t= here's + * none. The caller must check the return value for being non-NULL if need= ed. + * The return value of this function should not depend on whether we're in= the + * runtime or not. + */ +void *kmsan_get_metadata(void *address, bool is_origin) +{ + u64 addr =3D (u64)address, pad, off; + struct page *page; + void *ret; + + if (is_origin && !IS_ALIGNED(addr, KMSAN_ORIGIN_SIZE)) { + pad =3D addr % KMSAN_ORIGIN_SIZE; + addr -=3D pad; + } + address =3D (void *)addr; + if (kmsan_internal_is_vmalloc_addr(address) || + kmsan_internal_is_module_addr(address)) + return (void *)vmalloc_meta(address, is_origin); + + page =3D virt_to_page_or_null(address); + if (!page) + return NULL; + if (!page_has_metadata(page)) + return NULL; + off =3D addr % PAGE_SIZE; + + ret =3D (is_origin ? origin_ptr_for(page) : shadow_ptr_for(page)) + off; + return ret; +} diff --git a/scripts/Makefile.kmsan b/scripts/Makefile.kmsan new file mode 100644 index 0000000000000..9793591f9855c --- /dev/null +++ b/scripts/Makefile.kmsan @@ -0,0 +1 @@ +export CFLAGS_KMSAN :=3D -fsanitize=3Dkernel-memory diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 79be57fdd32a4..a96cf2a5d1c09 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -162,6 +162,15 @@ _c_flags +=3D $(if $(patsubst n%,, \ endif endif =20 +ifeq ($(CONFIG_KMSAN),y) +_c_flags +=3D $(if $(patsubst n%,, \ + $(KMSAN_SANITIZE_$(basetarget).o)$(KMSAN_SANITIZE)y), \ + $(CFLAGS_KMSAN)) +_c_flags +=3D $(if $(patsubst n%,, \ + $(KMSAN_ENABLE_CHECKS_$(basetarget).o)$(KMSAN_ENABLE_CHECKS)y), \ + , -mllvm -msan-disable-checks=3D1) +endif + ifeq ($(CONFIG_UBSAN),y) _c_flags +=3D $(if $(patsubst n%,, \ $(UBSAN_SANITIZE_$(basetarget).o)$(UBSAN_SANITIZE)$(CONFIG_UBSAN_SANITIZ= E_ALL)), \ --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D64FC433F5 for ; Tue, 29 Mar 2022 12:42:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233348AbiC2Mnw (ORCPT ); Tue, 29 Mar 2022 08:43:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236458AbiC2Mm7 (ORCPT ); Tue, 29 Mar 2022 08:42:59 -0400 Received: from mail-ed1-x54a.google.com (mail-ed1-x54a.google.com [IPv6:2a00:1450:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A0F9220336 for ; Tue, 29 Mar 2022 05:41:09 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id s9-20020a50d489000000b00418d556edbdso10959907edi.4 for ; Tue, 29 Mar 2022 05:41:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=FHzHVDPYZMTi95ptCkFXfySj60BESZp+qG5LjWpEp7c=; b=sWW5tRocZxxBnyH5c+5bB9SrN8yBbtlo2fkEMJuym0RIhB42RkiLDf+Mt3MIvJwiyJ 7j0vQ9s012H9UhxvQGmO+OVLPDT4DOl4vdbuAKldQJWeBJMxzqghX+s69XDhPtPnFmSZ ln18qWHYMmGUWOUIknOM0Bl7/4fn3Ax931TwAMeVd4qkvriskK/u0kVEIOnyYuiKjd5B kjzHcwWRbWcIxcxK6/78moEPo1Rs5jsyltN2n8NJo34SDw3L3nYlRBVlVJYFqaAjGTWX /iZyyw30rrol8h6QI3lmyhTL/EJEuNjLY2dUKHqXYZa6vP163p1YbzZ9JXRJ4sZt3h97 4xOQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=FHzHVDPYZMTi95ptCkFXfySj60BESZp+qG5LjWpEp7c=; b=UTGwQkS/ureRQrwSWHjN8KN3GSb4Y6gEIAEx0/Vba7RJACDK3hjTXcD+B5rESdK91P 4kr7lRCe9GMFXDlj9Yez9hcQZX89WHrKa0IgEEr6nGhL3imYevaVCZ1HhVhzUXThnUAk 16ipUZ872vMaAVkyzaGlQabrdH8EeNep6fUSl0EZX9otcI040MIEaayQiFqLFp+wUx/C k+PCQREmXl/tZqgfOqJ0XlGntVbbImxqtz1opmyxnP5qLQvjqRrk7CKQmzyaZzzV64dU fQ4NW7D9KuVlKh2zfh1FCZ1tAWtLUa4azKxz42/3Z/W/Iih3XFZsyDxsbwyv68UDg3OJ 5I0g== X-Gm-Message-State: AOAM531aiGktYKIamhARcHvRPJ3z+za2yEMdEkpfGGlGyuij5wVYLA2n 47zVqPojJ2mEizQ/tcvWfhCryBCsipg= X-Google-Smtp-Source: ABdhPJxIjE0+jxZBSo1pLmOTWSGay+gWDn7tl9m8Nl4sQMVHZ9JOsMlLrJDRqSA80Wdi3w3BwjBTXdlkc28= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:a1d3:b0:6d0:80ea:2fde with SMTP id bx19-20020a170906a1d300b006d080ea2fdemr33544446ejb.344.1648557667490; Tue, 29 Mar 2022 05:41:07 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:43 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-15-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 14/48] kmsan: implement kmsan_init(), initialize READ_ONCE_NOCHECK() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" kmsan_init() is a macro that takes a possibly uninitialized value and returns an initialized value of the same type. It can be used e.g. in cases when a value comes from non-instrumented code to avoid false positive reports. In particular, we use kmsan_init() in READ_ONCE_NOCHECK() so that it returns initialized values. This helps defeat false positives e.g. from leftover stack contents accessed by stack unwinders. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Icd1260073666f944922f031bfb6= 762379ba1fa38 --- include/asm-generic/rwonce.h | 5 +++-- include/linux/kmsan-checks.h | 40 ++++++++++++++++++++++++++++++++++++ mm/kmsan/Makefile | 5 ++++- mm/kmsan/annotations.c | 28 +++++++++++++++++++++++++ 4 files changed, 75 insertions(+), 3 deletions(-) create mode 100644 mm/kmsan/annotations.c diff --git a/include/asm-generic/rwonce.h b/include/asm-generic/rwonce.h index 8d0a6280e9824..7cf993af8e1ea 100644 --- a/include/asm-generic/rwonce.h +++ b/include/asm-generic/rwonce.h @@ -25,6 +25,7 @@ #include #include #include +#include =20 /* * Yes, this permits 64-bit accesses on 32-bit architectures. These will @@ -69,14 +70,14 @@ unsigned long __read_once_word_nocheck(const void *addr) =20 /* * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need to load a - * word from memory atomically but without telling KASAN/KCSAN. This is + * word from memory atomically but without telling KASAN/KCSAN/KMSAN. This= is * usually used by unwinding code when walking the stack of a running proc= ess. */ #define READ_ONCE_NOCHECK(x) \ ({ \ compiletime_assert(sizeof(x) =3D=3D sizeof(unsigned long), \ "Unsupported access size for READ_ONCE_NOCHECK()."); \ - (typeof(x))__read_once_word_nocheck(&(x)); \ + kmsan_init((typeof(x))__read_once_word_nocheck(&(x))); \ }) =20 static __no_kasan_or_inline diff --git a/include/linux/kmsan-checks.h b/include/linux/kmsan-checks.h index a6522a0c28df9..ecd8336190fc0 100644 --- a/include/linux/kmsan-checks.h +++ b/include/linux/kmsan-checks.h @@ -14,6 +14,44 @@ =20 #ifdef CONFIG_KMSAN =20 +/* + * Helper functions that mark the return value initialized. + * See mm/kmsan/annotations.c. + */ +u8 kmsan_init_1(u8 value); +u16 kmsan_init_2(u16 value); +u32 kmsan_init_4(u32 value); +u64 kmsan_init_8(u64 value); + +static inline void *kmsan_init_ptr(void *ptr) +{ + return (void *)kmsan_init_8((u64)ptr); +} + +static inline char kmsan_init_char(char value) +{ + return (u8)kmsan_init_1((u8)value); +} + +#define __decl_kmsan_init_type(type, fn) unsigned type : fn, signed type := fn + +/** + * kmsan_init - Make the value initialized. + * @val: 1-, 2-, 4- or 8-byte integer that may be treated as uninitialized= by + * KMSAN. + * + * Return: value of @val that KMSAN treats as initialized. + */ +#define kmsan_init(val) = \ + ( \ + (typeof(val))(_Generic((val), \ + __decl_kmsan_init_type(char, kmsan_init_1), \ + __decl_kmsan_init_type(short, kmsan_init_2), \ + __decl_kmsan_init_type(int, kmsan_init_4), \ + __decl_kmsan_init_type(long, kmsan_init_8), \ + char : kmsan_init_char, \ + void * : kmsan_init_ptr)(val))) + /** * kmsan_poison_memory() - Mark the memory range as uninitialized. * @address: address to start with. @@ -48,6 +86,8 @@ void kmsan_check_memory(const void *address, size_t size); =20 #else =20 +#define kmsan_init(value) (value) + static inline void kmsan_poison_memory(const void *address, size_t size, gfp_t flags) { diff --git a/mm/kmsan/Makefile b/mm/kmsan/Makefile index a80dde1de7048..73b705cbf75b9 100644 --- a/mm/kmsan/Makefile +++ b/mm/kmsan/Makefile @@ -1,9 +1,11 @@ -obj-y :=3D core.o instrumentation.o hooks.o report.o shadow.o +obj-y :=3D core.o instrumentation.o hooks.o report.o shadow.o annotations.o =20 KMSAN_SANITIZE :=3D n KCOV_INSTRUMENT :=3D n UBSAN_SANITIZE :=3D n =20 +KMSAN_SANITIZE_kmsan_annotations.o :=3D y + # Disable instrumentation of KMSAN runtime with other tools. CC_FLAGS_KMSAN_RUNTIME :=3D -fno-stack-protector CC_FLAGS_KMSAN_RUNTIME +=3D $(call cc-option,-fno-conserve-stack) @@ -11,6 +13,7 @@ CC_FLAGS_KMSAN_RUNTIME +=3D -DDISABLE_BRANCH_PROFILING =20 CFLAGS_REMOVE.o =3D $(CC_FLAGS_FTRACE) =20 +CFLAGS_annotations.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_core.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_hooks.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_instrumentation.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) diff --git a/mm/kmsan/annotations.c b/mm/kmsan/annotations.c new file mode 100644 index 0000000000000..8ccde90bcd12b --- /dev/null +++ b/mm/kmsan/annotations.c @@ -0,0 +1,28 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KMSAN annotations. + * + * The kmsan_init_SIZE functions reside in a separate translation unit to + * prevent inlining them. Clang may inline functions marked with + * __no_sanitize_memory attribute into functions without it, which effecti= vely + * results in ignoring the attribute. + * + * Copyright (C) 2017-2022 Google LLC + * Author: Alexander Potapenko + * + */ + +#include +#include + +#define DECLARE_KMSAN_INIT(size, t) = \ + __no_sanitize_memory t kmsan_init_##size(t value) \ + { \ + return value; \ + } \ + EXPORT_SYMBOL(kmsan_init_##size) + +DECLARE_KMSAN_INIT(1, u8); +DECLARE_KMSAN_INIT(2, u16); +DECLARE_KMSAN_INIT(4, u32); +DECLARE_KMSAN_INIT(8, u64); --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7157C433F5 for ; Tue, 29 Mar 2022 12:42:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236470AbiC2Mn6 (ORCPT ); Tue, 29 Mar 2022 08:43:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236528AbiC2Mm7 (ORCPT ); Tue, 29 Mar 2022 08:42:59 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5D90220B1B for ; Tue, 29 Mar 2022 05:41:11 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id jx2-20020a170907760200b006dfc374c502so8134023ejc.7 for ; Tue, 29 Mar 2022 05:41:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=sAExT7SSSN10XTsfQtAC8lmzod9gG+fvZFiYZO+nEYE=; b=D6F1SQpsqCx29Z1hyC0VZ9QPHGSIXqGIXoKTX1t41Ec2/BI7aZiEaJshNZSDnAZ7nS N0yqCJQ1PeJoGgtRjd8nBmpux8LP0+eBYvj27cf5rvJF2ttWc9OSvKWGhvOFaPjbxaN2 iLVvCLMm9/YCzNogYHden+UNUQUg7Gu8PKy6sCZn5PGrBo+vg4vbm5DyaR/Hu6lfTDxe bBZIR0eLro+O+0mwMGrZMyVEi8Yrq+V0gNiY+vIntbaE/O8ubQGR276mculXvjUvzEt3 F9sCA4kDsGFBoicnwuxq29jXZYbDMu4MZup8guVtOlSWws6VucaX5kmprRui40j9NH5o h+ug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=sAExT7SSSN10XTsfQtAC8lmzod9gG+fvZFiYZO+nEYE=; b=X/RbhvhXIWXiqbVsL4ONfUFh5K3isUgNrlk2Pjf3h8hoH0hwzLuei2njOJmxiywFrm N2EvZKxq29G3VizrrE4HZuzmSOqqJEF2xRFwonNRLHCwWewvmqTP2zhfU21eWwxshveX mBeCbKSBjWwUA8Xj7zBuTxlm1j+EJIRQ16YUP2ft5m4AUSF3IWg28y0FeI3TbJ3e0x3J iB28WYXfEjrPjjxLT8rgZ1HnhjYu3buzIjAlrEyFqxgA3+HLeBDH5Bnfwg9/HQiAwS40 YL8TC6V4HAQtSdlUIcDJOs//C5pOTD5572z4VGWJXZJ01vKSrnUVn0/EwCdi4t8mm2vk cFcg== X-Gm-Message-State: AOAM531dBHivvGKk62Sd4lOrrywhIab3oyFWv+G0y4QnOTvKtViUIpBC /bdWNjYjw6GO2Ahfq+m4WKeb2XYYs14= X-Google-Smtp-Source: ABdhPJxiJ9oKFDmYGNh7Br69DkPJpOkn+XAOKfovDuKDd9aMeedhy/6xJEB6s/tleVFOHEB0WVg/Meo2NMo= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a05:6402:d69:b0:418:f7bd:b076 with SMTP id ec41-20020a0564020d6900b00418f7bdb076mr4306755edb.268.1648557669972; Tue, 29 Mar 2022 05:41:09 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:44 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-16-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 15/48] kmsan: disable instrumentation of unsupported common kernel code From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" EFI stub cannot be linked with KMSAN runtime, so we disable instrumentation for it. Instrumenting kcov, stackdepot or lockdep leads to infinite recursion caused by instrumentation hooks calling instrumented code again. This patch was previously part of "kmsan: disable KMSAN instrumentation for certain kernel parts", but was split away per Mark Rutland's request. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I41ae706bd3474f074f6a870bfc3= f0f90e9c720f7 --- drivers/firmware/efi/libstub/Makefile | 1 + kernel/Makefile | 1 + kernel/locking/Makefile | 3 ++- lib/Makefile | 1 + 4 files changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/l= ibstub/Makefile index d0537573501e9..81432d0c904b1 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -46,6 +46,7 @@ GCOV_PROFILE :=3D n # Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE :=3D n KCSAN_SANITIZE :=3D n +KMSAN_SANITIZE :=3D n UBSAN_SANITIZE :=3D n OBJECT_FILES_NON_STANDARD :=3D y =20 diff --git a/kernel/Makefile b/kernel/Makefile index 56f4ee97f3284..80f6cfb60c020 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -39,6 +39,7 @@ KCOV_INSTRUMENT_kcov.o :=3D n KASAN_SANITIZE_kcov.o :=3D n KCSAN_SANITIZE_kcov.o :=3D n UBSAN_SANITIZE_kcov.o :=3D n +KMSAN_SANITIZE_kcov.o :=3D n CFLAGS_kcov.o :=3D $(call cc-option, -fno-conserve-stack) -fno-stack-prote= ctor =20 # Don't instrument error handlers diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile index d51cabf28f382..ea925731fa40f 100644 --- a/kernel/locking/Makefile +++ b/kernel/locking/Makefile @@ -5,8 +5,9 @@ KCOV_INSTRUMENT :=3D n =20 obj-y +=3D mutex.o semaphore.o rwsem.o percpu-rwsem.o =20 -# Avoid recursion lockdep -> KCSAN -> ... -> lockdep. +# Avoid recursion lockdep -> sanitizer -> ... -> lockdep. KCSAN_SANITIZE_lockdep.o :=3D n +KMSAN_SANITIZE_lockdep.o :=3D n =20 ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_lockdep.o =3D $(CC_FLAGS_FTRACE) diff --git a/lib/Makefile b/lib/Makefile index 300f569c626b0..0ac9b38ec172e 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -269,6 +269,7 @@ obj-$(CONFIG_IRQ_POLL) +=3D irq_poll.o CFLAGS_stackdepot.o +=3D -fno-builtin obj-$(CONFIG_STACKDEPOT) +=3D stackdepot.o KASAN_SANITIZE_stackdepot.o :=3D n +KMSAN_SANITIZE_stackdepot.o :=3D n KCOV_INSTRUMENT_stackdepot.o :=3D n =20 obj-$(CONFIG_REF_TRACKER) +=3D ref_tracker.o --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8532DC433FE for ; Tue, 29 Mar 2022 12:42:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236556AbiC2MoD (ORCPT ); Tue, 29 Mar 2022 08:44:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33914 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236546AbiC2MnA (ORCPT ); Tue, 29 Mar 2022 08:43:00 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4A27E220FDA for ; Tue, 29 Mar 2022 05:41:14 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id gx12-20020a1709068a4c00b006df7e8181ceso8122582ejc.10 for ; Tue, 29 Mar 2022 05:41:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=17K480cFHZmjgZnEKs0kvaSf6Wt6+7fFqZhB6I4ek4M=; b=RSDNW7nZXrX14ECEyw7iYD8PmPG9kTQkYLbWQ7qMATA0/b6xXjIDXSHO98HP2EtZKs lhAoCw7gzmWs/rvYGDw/eTGXSRrJlJh6DUibcUhZyQhiQH6E63/DD0cNXhwbf8sHDm1W k8DlOA7/CM9UnHu1KQJYWBvxHNHY5VbXChFuhjmADE4ZsvBWU5u5hHrXpd+CNyWFkine L34oSIh5HCj7mFNxyr5ujACe/1SMjwIg4y0zKxsN8e+BwlG9OCcKTrKsNaEfTRS+Hsmn uKtH1oVpOBVYoMma60yhuXibPqsneRA9ZLArVfhZgEkVmZVR70UWp2VL4AZQRC8m6TIs gR4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=17K480cFHZmjgZnEKs0kvaSf6Wt6+7fFqZhB6I4ek4M=; b=qn7M1g2wwvGVXiDR8k8Nr12F0EOMi5dWRtxHPBXTCnXlrbXbKLWx0ua9AUamvi63ON yUGGDytDchrWObJ5JYmQjbA0ArAPF9wvcQ5Y7QJZJRKCS3DwSigq4YG8xrWVcHRbRber F+FuMVb/Ly/dnkmCLgTyA8hZbWQrKbz45ByhHsB6TPVBywcAdETiXGYY6u3jtB4yoE60 tY6QEC5R7ru2wJsbOfxt06DXBAme/ULmhp4bbDC8P98njN9RL8kY+feyJJ4w+PcMhWtf 5YOPWBcjqh2N+nQd8TG4X2JJR80yCKOyVUgpjpd1YEnEvyi8PGE108Z1xyHJACBPrku9 LY6Q== X-Gm-Message-State: AOAM532g7ZHRZWWylO+l1dyJ6lmWp0TaauhPleFfEiowYsKjuP2kifQh W1Ti16zASiupP8wyirHDp09YEY6Fraw= X-Google-Smtp-Source: ABdhPJw7IcXW/4bj+dfFYbcSuDH6uP+LYtDkdrlnTYVetr1ku4F+UEshV4bZLv/czt62R1ghVW3NtkuMjeM= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a50:baa1:0:b0:418:849a:c66a with SMTP id x30-20020a50baa1000000b00418849ac66amr4402991ede.234.1648557672349; Tue, 29 Mar 2022 05:41:12 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:45 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-17-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 16/48] MAINTAINERS: add entry for KMSAN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add entry for KMSAN maintainers/reviewers. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Ic5836c2bceb6b63f71a60d3327d= 18af3aa3dab77 --- MAINTAINERS | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index cd0f68d4a34a6..4053523a1e890 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -10721,6 +10721,18 @@ F: kernel/kmod.c F: lib/test_kmod.c F: tools/testing/selftests/kmod/ =20 +KMSAN +M: Alexander Potapenko +R: Marco Elver +R: Dmitry Vyukov +L: kasan-dev@googlegroups.com +S: Maintained +F: Documentation/dev-tools/kmsan.rst +F: include/linux/kmsan*.h +F: lib/Kconfig.kmsan +F: mm/kmsan/ +F: scripts/Makefile.kmsan + KPROBES M: Naveen N. Rao M: Anil S Keshavamurthy --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A1B3C433FE for ; Tue, 29 Mar 2022 12:42:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236513AbiC2MoJ (ORCPT ); Tue, 29 Mar 2022 08:44:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236466AbiC2MnB (ORCPT ); Tue, 29 Mar 2022 08:43:01 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA80C223840 for ; Tue, 29 Mar 2022 05:41:16 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id m12-20020a1709062acc00b006cfc98179e2so8132915eje.6 for ; Tue, 29 Mar 2022 05:41:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=yKduOyp99ugSQWVTLSsIolDzuknPE7+2zaI7xOYspzg=; b=aLGX3+btp72E9I8iIP13PehJlqEjCIHhZ5kJ0YIImU9bsuvDP6AjUX4QPmgUH7A8Rb B7bMzdl+XRl1RkpaCUZyltrTlhfYjnKMCZgY3w0Uct7bJ9T9jZ48zBNKDY3DHaTIM9iv U81PRQmRtd1z4pn9iCih2gfAEtcNRfKIx+xJ5o1fRVKFgV/8cgKVrqOt2TF6XtH8HRY2 YW5JZvAc00JXKzkJOz/l5dJNsp/yZNWAr0xJJe9E4WoCYcSQBT9FGSSvzcYJHIdEKYQa YxAZyvLBpD8pvgprSSiDq5FakEZfbL7eNIXyrhnHP4w5zS0OkSn3kUZQ28xwQhtBkdV1 bCRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=yKduOyp99ugSQWVTLSsIolDzuknPE7+2zaI7xOYspzg=; b=KeOXWHoOiMNNbCoUVm76mQvqEEwKboolWHmYGyxRLWOZoJhPHeE7Hy/QMOSDKctSH8 Sdi14+xDRdiUccwvJJS0YfLltcAY01xeVzu0HWueqUz6GHnFskCZ3ikkAAlQY53kc3tM SfqPy73OmPb8zKoX6kYdqpaHXx4sx3hdldvoQg3xwVbA799jkYUOFhKT/Bb6iz4eJ12k HXMvtPXVacwFplG1OJu2P/Ljbb9lMANxevSdxk39P50M/8RP6nVVzOEozaGQ+mZWN/5A CTp+X3IMuFWwpOgOeHKIIYa80NdaLVQrz66ZKjgrgxo0wEhj+udCg5H65/u6sWO2kkd/ gA8Q== X-Gm-Message-State: AOAM532JnCL3sjgL6XHU6q7FnsCfOg0TGDIdUofEMN5xkfHgBWmTlydS NCRkwobGtEzJ3aC67tCK9G4V6aa+XkM= X-Google-Smtp-Source: ABdhPJxGPoJ8SsJw1yoJtEPicRhFIsuEKTSWyo8YXKacL9FRobmfyn/uSDVKER220NA/RkMYrCJCsHs74w8= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a50:9eaa:0:b0:418:f708:f59c with SMTP id a39-20020a509eaa000000b00418f708f59cmr4214006edf.333.1648557675310; Tue, 29 Mar 2022 05:41:15 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:46 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-18-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 17/48] kmsan: mm: maintain KMSAN metadata for page operations From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Insert KMSAN hooks that make the necessary bookkeeping changes: - poison page shadow and origins in alloc_pages()/free_page(); - clear page shadow and origins in clear_page(), copy_user_highpage(); - copy page metadata in copy_highpage(), wp_page_copy(); - handle vmap()/vunmap()/iounmap(); Signed-off-by: Alexander Potapenko --- v2: -- move page metadata hooks implementation here -- remove call to kmsan_memblock_free_pages() Link: https://linux-review.googlesource.com/id/I6d4f53a0e7eab46fa29f0348f30= 95d9f2e326850 --- arch/x86/include/asm/page_64.h | 13 ++++ arch/x86/mm/ioremap.c | 3 + include/linux/highmem.h | 3 + include/linux/kmsan.h | 123 +++++++++++++++++++++++++++++++++ mm/internal.h | 6 ++ mm/kmsan/hooks.c | 87 +++++++++++++++++++++++ mm/kmsan/shadow.c | 114 ++++++++++++++++++++++++++++++ mm/memory.c | 2 + mm/page_alloc.c | 11 +++ mm/vmalloc.c | 20 +++++- 10 files changed, 380 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h index e9c86299b8351..36e270a8ea9a4 100644 --- a/arch/x86/include/asm/page_64.h +++ b/arch/x86/include/asm/page_64.h @@ -45,14 +45,27 @@ void clear_page_orig(void *page); void clear_page_rep(void *page); void clear_page_erms(void *page); =20 +/* This is an assembly header, avoid including too much of kmsan.h */ +#ifdef CONFIG_KMSAN +void kmsan_unpoison_memory(const void *addr, size_t size); +#endif +__no_sanitize_memory static inline void clear_page(void *page) { +#ifdef CONFIG_KMSAN + /* alternative_call_2() changes @page. */ + void *page_copy =3D page; +#endif alternative_call_2(clear_page_orig, clear_page_rep, X86_FEATURE_REP_GOOD, clear_page_erms, X86_FEATURE_ERMS, "=3DD" (page), "0" (page) : "cc", "memory", "rax", "rcx"); +#ifdef CONFIG_KMSAN + /* Clear KMSAN shadow for the pages that have it. */ + kmsan_unpoison_memory(page_copy, PAGE_SIZE); +#endif } =20 void copy_page(void *to, void *from); diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 17a492c273069..0da8608778221 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -17,6 +17,7 @@ #include #include #include +#include =20 #include #include @@ -474,6 +475,8 @@ void iounmap(volatile void __iomem *addr) return; } =20 + kmsan_iounmap_page_range((unsigned long)addr, + (unsigned long)addr + get_vm_area_size(p)); memtype_free(p->phys_addr, p->phys_addr + get_vm_area_size(p)); =20 /* Finally remove it */ diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 39bb9b47fa9cd..3e1898a44d7e3 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -277,6 +278,7 @@ static inline void copy_user_highpage(struct page *to, = struct page *from, vfrom =3D kmap_local_page(from); vto =3D kmap_local_page(to); copy_user_page(vto, vfrom, vaddr, to); + kmsan_unpoison_memory(page_address(to), PAGE_SIZE); kunmap_local(vto); kunmap_local(vfrom); } @@ -292,6 +294,7 @@ static inline void copy_highpage(struct page *to, struc= t page *from) vfrom =3D kmap_local_page(from); vto =3D kmap_local_page(to); copy_page(vto, vfrom); + kmsan_copy_page_meta(to, from); kunmap_local(vto); kunmap_local(vfrom); } diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index 4e35f43eceaa9..da41850b46cbd 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -42,6 +42,129 @@ struct kmsan_ctx { bool allow_reporting; }; =20 +/** + * kmsan_alloc_page() - Notify KMSAN about an alloc_pages() call. + * @page: struct page pointer returned by alloc_pages(). + * @order: order of allocated struct page. + * @flags: GFP flags used by alloc_pages() + * + * KMSAN marks 1<<@order pages starting at @page as uninitialized, unless + * @flags contain __GFP_ZERO. + */ +void kmsan_alloc_page(struct page *page, unsigned int order, gfp_t flags); + +/** + * kmsan_free_page() - Notify KMSAN about a free_pages() call. + * @page: struct page pointer passed to free_pages(). + * @order: order of deallocated struct page. + * + * KMSAN marks freed memory as uninitialized. + */ +void kmsan_free_page(struct page *page, unsigned int order); + +/** + * kmsan_copy_page_meta() - Copy KMSAN metadata between two pages. + * @dst: destination page. + * @src: source page. + * + * KMSAN copies the contents of metadata pages for @src into the metadata = pages + * for @dst. If @dst has no associated metadata pages, nothing happens. + * If @src has no associated metadata pages, @dst metadata pages are unpoi= soned. + */ +void kmsan_copy_page_meta(struct page *dst, struct page *src); + +/** + * kmsan_map_kernel_range_noflush() - Notify KMSAN about a vmap. + * @start: start of vmapped range. + * @end: end of vmapped range. + * @prot: page protection flags used for vmap. + * @pages: array of pages. + * @page_shift: page_shift passed to vmap_range_noflush(). + * + * KMSAN maps shadow and origin pages of @pages into contiguous ranges in + * vmalloc metadata address range. + */ +void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, + pgprot_t prot, struct page **pages, + unsigned int page_shift); + +/** + * kmsan_vunmap_kernel_range_noflush() - Notify KMSAN about a vunmap. + * @start: start of vunmapped range. + * @end: end of vunmapped range. + * + * KMSAN unmaps the contiguous metadata ranges created by + * kmsan_map_kernel_range_noflush(). + */ +void kmsan_vunmap_range_noflush(unsigned long start, unsigned long end); + +/** + * kmsan_ioremap_page_range() - Notify KMSAN about a ioremap_page_range() = call. + * @addr: range start. + * @end: range end. + * @phys_addr: physical range start. + * @prot: page protection flags used for ioremap_page_range(). + * @page_shift: page_shift argument passed to vmap_range_noflush(). + * + * KMSAN creates new metadata pages for the physical pages mapped into the + * virtual memory. + */ +void kmsan_ioremap_page_range(unsigned long addr, unsigned long end, + phys_addr_t phys_addr, pgprot_t prot, + unsigned int page_shift); + +/** + * kmsan_iounmap_page_range() - Notify KMSAN about a iounmap_page_range() = call. + * @start: range start. + * @end: range end. + * + * KMSAN unmaps the metadata pages for the given range and, unlike for + * vunmap_page_range(), also deallocates them. + */ +void kmsan_iounmap_page_range(unsigned long start, unsigned long end); + +#else + +static inline int kmsan_alloc_page(struct page *page, unsigned int order, + gfp_t flags) +{ + return 0; +} + +static inline void kmsan_free_page(struct page *page, unsigned int order) +{ +} + +static inline void kmsan_copy_page_meta(struct page *dst, struct page *src) +{ +} + +static inline void kmsan_vmap_pages_range_noflush(unsigned long start, + unsigned long end, + pgprot_t prot, + struct page **pages, + unsigned int page_shift) +{ +} + +static inline void kmsan_vunmap_range_noflush(unsigned long start, + unsigned long end) +{ +} + +static inline void kmsan_ioremap_page_range(unsigned long start, + unsigned long end, + phys_addr_t phys_addr, + pgprot_t prot, + unsigned int page_shift) +{ +} + +static inline void kmsan_iounmap_page_range(unsigned long start, + unsigned long end) +{ +} + #endif =20 #endif /* _LINUX_KMSAN_H */ diff --git a/mm/internal.h b/mm/internal.h index d80300392a194..2d8ca0ae4774f 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -713,8 +713,14 @@ int vmap_pages_range_noflush(unsigned long addr, unsig= ned long end, } #endif =20 +int __vmap_pages_range_noflush(unsigned long addr, unsigned long end, + pgprot_t prot, struct page **pages, + unsigned int page_shift); + void vunmap_range_noflush(unsigned long start, unsigned long end); =20 +void __vunmap_range_noflush(unsigned long start, unsigned long end); + int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, unsigned long addr, int page_nid, int *flags); =20 diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index 4ac62fa67a02a..5d886df57adca 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -26,6 +26,93 @@ * skipping effects of functions like memset() inside instrumented code. */ =20 +static unsigned long vmalloc_shadow(unsigned long addr) +{ + return (unsigned long)kmsan_get_metadata((void *)addr, + KMSAN_META_SHADOW); +} + +static unsigned long vmalloc_origin(unsigned long addr) +{ + return (unsigned long)kmsan_get_metadata((void *)addr, + KMSAN_META_ORIGIN); +} + +void kmsan_vunmap_range_noflush(unsigned long start, unsigned long end) +{ + __vunmap_range_noflush(vmalloc_shadow(start), vmalloc_shadow(end)); + __vunmap_range_noflush(vmalloc_origin(start), vmalloc_origin(end)); + flush_cache_vmap(vmalloc_shadow(start), vmalloc_shadow(end)); + flush_cache_vmap(vmalloc_origin(start), vmalloc_origin(end)); +} +EXPORT_SYMBOL(kmsan_vunmap_range_noflush); + +/* + * This function creates new shadow/origin pages for the physical pages ma= pped + * into the virtual memory. If those physical pages already had shadow/ori= gin, + * those are ignored. + */ +void kmsan_ioremap_page_range(unsigned long start, unsigned long end, + phys_addr_t phys_addr, pgprot_t prot, + unsigned int page_shift) +{ + gfp_t gfp_mask =3D GFP_KERNEL | __GFP_ZERO; + struct page *shadow, *origin; + unsigned long off =3D 0; + int i, nr; + + if (!kmsan_enabled || kmsan_in_runtime()) + return; + + nr =3D (end - start) / PAGE_SIZE; + kmsan_enter_runtime(); + for (i =3D 0; i < nr; i++, off +=3D PAGE_SIZE) { + shadow =3D alloc_pages(gfp_mask, 1); + origin =3D alloc_pages(gfp_mask, 1); + __vmap_pages_range_noflush( + vmalloc_shadow(start + off), + vmalloc_shadow(start + off + PAGE_SIZE), prot, &shadow, + page_shift); + __vmap_pages_range_noflush( + vmalloc_origin(start + off), + vmalloc_origin(start + off + PAGE_SIZE), prot, &origin, + page_shift); + } + flush_cache_vmap(vmalloc_shadow(start), vmalloc_shadow(end)); + flush_cache_vmap(vmalloc_origin(start), vmalloc_origin(end)); + kmsan_leave_runtime(); +} +EXPORT_SYMBOL(kmsan_ioremap_page_range); + +void kmsan_iounmap_page_range(unsigned long start, unsigned long end) +{ + unsigned long v_shadow, v_origin; + struct page *shadow, *origin; + int i, nr; + + if (!kmsan_enabled || kmsan_in_runtime()) + return; + + nr =3D (end - start) / PAGE_SIZE; + kmsan_enter_runtime(); + v_shadow =3D (unsigned long)vmalloc_shadow(start); + v_origin =3D (unsigned long)vmalloc_origin(start); + for (i =3D 0; i < nr; i++, v_shadow +=3D PAGE_SIZE, v_origin +=3D PAGE_SI= ZE) { + shadow =3D kmsan_vmalloc_to_page_or_null((void *)v_shadow); + origin =3D kmsan_vmalloc_to_page_or_null((void *)v_origin); + __vunmap_range_noflush(v_shadow, vmalloc_shadow(end)); + __vunmap_range_noflush(v_origin, vmalloc_origin(end)); + if (shadow) + __free_pages(shadow, 1); + if (origin) + __free_pages(origin, 1); + } + flush_cache_vmap(vmalloc_shadow(start), vmalloc_shadow(end)); + flush_cache_vmap(vmalloc_origin(start), vmalloc_origin(end)); + kmsan_leave_runtime(); +} +EXPORT_SYMBOL(kmsan_iounmap_page_range); + /* Functions from kmsan-checks.h follow. */ void kmsan_poison_memory(const void *address, size_t size, gfp_t flags) { diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c index de58cfbc55b9d..8fe6a5ed05e67 100644 --- a/mm/kmsan/shadow.c +++ b/mm/kmsan/shadow.c @@ -184,3 +184,117 @@ void *kmsan_get_metadata(void *address, bool is_origi= n) ret =3D (is_origin ? origin_ptr_for(page) : shadow_ptr_for(page)) + off; return ret; } + +void kmsan_copy_page_meta(struct page *dst, struct page *src) +{ + if (!kmsan_enabled || kmsan_in_runtime()) + return; + if (!dst || !page_has_metadata(dst)) + return; + if (!src || !page_has_metadata(src)) { + kmsan_internal_unpoison_memory(page_address(dst), PAGE_SIZE, + /*checked*/ false); + return; + } + + kmsan_enter_runtime(); + __memcpy(shadow_ptr_for(dst), shadow_ptr_for(src), PAGE_SIZE); + __memcpy(origin_ptr_for(dst), origin_ptr_for(src), PAGE_SIZE); + kmsan_leave_runtime(); +} + +void kmsan_alloc_page(struct page *page, unsigned int order, gfp_t flags) +{ + bool initialized =3D (flags & __GFP_ZERO) || !kmsan_enabled; + struct page *shadow, *origin; + depot_stack_handle_t handle; + int pages =3D 1 << order; + int i; + + if (!page) + return; + + shadow =3D shadow_page_for(page); + origin =3D origin_page_for(page); + + if (initialized) { + __memset(page_address(shadow), 0, PAGE_SIZE * pages); + __memset(page_address(origin), 0, PAGE_SIZE * pages); + return; + } + + /* Zero pages allocated by the runtime should also be initialized. */ + if (kmsan_in_runtime()) + return; + + __memset(page_address(shadow), -1, PAGE_SIZE * pages); + kmsan_enter_runtime(); + handle =3D kmsan_save_stack_with_flags(flags, /*extra_bits*/ 0); + kmsan_leave_runtime(); + /* + * Addresses are page-aligned, pages are contiguous, so it's ok + * to just fill the origin pages with |handle|. + */ + for (i =3D 0; i < PAGE_SIZE * pages / sizeof(handle); i++) + ((depot_stack_handle_t *)page_address(origin))[i] =3D handle; +} + +void kmsan_free_page(struct page *page, unsigned int order) +{ + if (!kmsan_enabled || kmsan_in_runtime()) + return; + kmsan_enter_runtime(); + kmsan_internal_poison_memory(page_address(page), + PAGE_SIZE << compound_order(page), + GFP_KERNEL, + KMSAN_POISON_CHECK | KMSAN_POISON_FREE); + kmsan_leave_runtime(); +} + +void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, + pgprot_t prot, struct page **pages, + unsigned int page_shift) +{ + unsigned long shadow_start, origin_start, shadow_end, origin_end; + struct page **s_pages, **o_pages; + int nr, i, mapped; + + if (!kmsan_enabled) + return; + + shadow_start =3D vmalloc_meta((void *)start, KMSAN_META_SHADOW); + shadow_end =3D vmalloc_meta((void *)end, KMSAN_META_SHADOW); + if (!shadow_start) + return; + + nr =3D (end - start) / PAGE_SIZE; + s_pages =3D kcalloc(nr, sizeof(struct page *), GFP_KERNEL); + o_pages =3D kcalloc(nr, sizeof(struct page *), GFP_KERNEL); + if (!s_pages || !o_pages) + goto ret; + for (i =3D 0; i < nr; i++) { + s_pages[i] =3D shadow_page_for(pages[i]); + o_pages[i] =3D origin_page_for(pages[i]); + } + prot =3D __pgprot(pgprot_val(prot) | _PAGE_NX); + prot =3D PAGE_KERNEL; + + origin_start =3D vmalloc_meta((void *)start, KMSAN_META_ORIGIN); + origin_end =3D vmalloc_meta((void *)end, KMSAN_META_ORIGIN); + kmsan_enter_runtime(); + mapped =3D __vmap_pages_range_noflush(shadow_start, shadow_end, prot, + s_pages, page_shift); + KMSAN_WARN_ON(mapped); + mapped =3D __vmap_pages_range_noflush(origin_start, origin_end, prot, + o_pages, page_shift); + KMSAN_WARN_ON(mapped); + kmsan_leave_runtime(); + flush_tlb_kernel_range(shadow_start, shadow_end); + flush_tlb_kernel_range(origin_start, origin_end); + flush_cache_vmap(shadow_start, shadow_end); + flush_cache_vmap(origin_start, origin_end); + +ret: + kfree(s_pages); + kfree(o_pages); +} diff --git a/mm/memory.c b/mm/memory.c index c125c4969913a..7465eb43e6d3e 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -52,6 +52,7 @@ #include #include #include +#include #include #include #include @@ -3026,6 +3027,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) put_page(old_page); return 0; } + kmsan_copy_page_meta(new_page, old_page); } =20 if (mem_cgroup_charge(page_folio(new_page), mm, GFP_KERNEL)) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3589febc6d319..98a066c0a9f63 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -1301,6 +1302,7 @@ static __always_inline bool free_pages_prepare(struct= page *page, VM_BUG_ON_PAGE(PageTail(page), page); =20 trace_mm_page_free(page, order); + kmsan_free_page(page, order); =20 if (unlikely(PageHWPoison(page)) && !order) { /* @@ -3679,6 +3681,14 @@ static struct page *rmqueue_pcplist(struct zone *pre= ferred_zone, /* * Allocate a page from the given zone. Use pcplists for order-0 allocatio= ns. */ + +/* + * Do not instrument rmqueue() with KMSAN. This function may call + * __msan_poison_alloca() through a call to set_pfnblock_flags_mask(). + * If __msan_poison_alloca() attempts to allocate pages for the stack depo= t, it + * may call rmqueue() again, which will result in a deadlock. + */ +__no_sanitize_memory static inline struct page *rmqueue(struct zone *preferred_zone, struct zone *zone, unsigned int order, @@ -5409,6 +5419,7 @@ struct page *__alloc_pages(gfp_t gfp, unsigned int or= der, int preferred_nid, } =20 trace_mm_page_alloc(page, order, alloc_gfp, ac.migratetype); + kmsan_alloc_page(page, order, alloc_gfp); =20 return page; } diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 4165304d35471..7bcbf7a08597a 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -321,6 +321,9 @@ int ioremap_page_range(unsigned long addr, unsigned lon= g end, err =3D vmap_range_noflush(addr, end, phys_addr, pgprot_nx(prot), ioremap_max_page_shift); flush_cache_vmap(addr, end); + if (!err) + kmsan_ioremap_page_range(addr, end, phys_addr, prot, + ioremap_max_page_shift); return err; } =20 @@ -420,7 +423,7 @@ static void vunmap_p4d_range(pgd_t *pgd, unsigned long = addr, unsigned long end, * * This is an internal function only. Do not use outside mm/. */ -void vunmap_range_noflush(unsigned long start, unsigned long end) +void __vunmap_range_noflush(unsigned long start, unsigned long end) { unsigned long next; pgd_t *pgd; @@ -442,6 +445,12 @@ void vunmap_range_noflush(unsigned long start, unsigne= d long end) arch_sync_kernel_mappings(start, end); } =20 +void vunmap_range_noflush(unsigned long start, unsigned long end) +{ + kmsan_vunmap_range_noflush(start, end); + __vunmap_range_noflush(start, end); +} + /** * vunmap_range - unmap kernel virtual addresses * @addr: start of the VM area to unmap @@ -576,7 +585,7 @@ static int vmap_small_pages_range_noflush(unsigned long= addr, unsigned long end, * * This is an internal function only. Do not use outside mm/. */ -int vmap_pages_range_noflush(unsigned long addr, unsigned long end, +int __vmap_pages_range_noflush(unsigned long addr, unsigned long end, pgprot_t prot, struct page **pages, unsigned int page_shift) { unsigned int i, nr =3D (end - addr) >> PAGE_SHIFT; @@ -602,6 +611,13 @@ int vmap_pages_range_noflush(unsigned long addr, unsig= ned long end, return 0; } =20 +int vmap_pages_range_noflush(unsigned long addr, unsigned long end, + pgprot_t prot, struct page **pages, unsigned int page_shift) +{ + kmsan_vmap_pages_range_noflush(addr, end, prot, pages, page_shift); + return __vmap_pages_range_noflush(addr, end, prot, pages, page_shift); +} + /** * vmap_pages_range - map pages to a kernel virtual address * @addr: start of the VM area to map --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8142C433EF for ; Tue, 29 Mar 2022 12:42:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236664AbiC2Mo3 (ORCPT ); Tue, 29 Mar 2022 08:44:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236488AbiC2MnE (ORCPT ); Tue, 29 Mar 2022 08:43:04 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A67BD21C046 for ; Tue, 29 Mar 2022 05:41:19 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id c31-20020a509fa2000000b004190d43d28fso10860828edf.9 for ; Tue, 29 Mar 2022 05:41:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=eLTwq5fXtDdDgS/orJshG1NPMtxpnPMwecHlrlYjY5k=; b=YeLodpZfduGO15yqSmZY77L+R71ULPMnJ6yUkyXtKqSlSSA54mtn2FcyNxxJVc4T8n Ps9eMetHiUKmh6e62QxJb+qy1wCTBSB9PsJGwttP10YPFhLiqtO3KCvAT2VGmKImTn5h FOXZ/dkZtREgpO/E7GOkbwTdi+os2zsItYWb7iH5IdjoGExdSbceax2P1ziSXdr+hgpK OMqfkCr+biZ8QakcknP/V/sQQP0lnJKG1x7AXoh5aOPYwyaJWOwVekm8k6WsAVaSt6u9 +09yHcZhlZUPQeEMReQIf2GWG6+2oppKnWRZv+PgK+qDgEndnY4xeZLppveUBoHHTq28 oreA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=eLTwq5fXtDdDgS/orJshG1NPMtxpnPMwecHlrlYjY5k=; b=ExJwrwXNValZf8LAj0/7ML6unO+3tmqb5M0Aff6ibH3GWoiPHYvs8NLmWhfOUIliK3 pqmgUc4Cn71hKPtIbKqNt67mVSneXSAFa+IiXZEP6wa3hLWqsTXg5kk1pYerLCmYv6ED dQTUL5wSwLQXHskKPM8mA362MsCvW9McduBp2SSIK57GBNrznuBszS7HuiiCORnjhPop htfPd570fskAXr1rjYXGwg8oe2ceqF9TM9zIJwYnb4VYjH53AezF9W6vdX5nZN3cQ7BC UFbBa0PZYbNIMt9yghhjrVtbqVDWQTJtjMUipdVnSsW5FFPYHXky/xdaUrekx5QcM4H5 /vzA== X-Gm-Message-State: AOAM530HBuZGisuhh5moTZs65Hj2Tc5xZRy+FGHPaeaepkyu7hyq7xDk iMxA+dpl42u/XrDNBBZh5UeZUkPmFp0= X-Google-Smtp-Source: ABdhPJzioc26w+W1I/VvZu1bf1qX6b/mh6UAssfjndgHHlyk+n1AtDxpbTRF9xgagMeR4K1GA1wf6PNlQSQ= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:1c10:b0:6da:6316:d009 with SMTP id nc16-20020a1709071c1000b006da6316d009mr34133251ejc.621.1648557677849; Tue, 29 Mar 2022 05:41:17 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:47 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-19-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 18/48] kmsan: mm: call KMSAN hooks from SLUB code From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" In order to report uninitialized memory coming from heap allocations KMSAN has to poison them unless they're created with __GFP_ZERO. It's handy that we need KMSAN hooks in the places where init_on_alloc/init_on_free initialization is performed. Signed-off-by: Alexander Potapenko --- v2: -- move the implementation of SLUB hooks here Link: https://linux-review.googlesource.com/id/I6954b386c5c5d7f99f48bb6cbcc= 74b75136ce86e --- include/linux/kmsan.h | 57 ++++++++++++++++++++++++++++++ mm/kmsan/hooks.c | 80 +++++++++++++++++++++++++++++++++++++++++++ mm/slab.h | 1 + mm/slub.c | 21 ++++++++++-- 4 files changed, 157 insertions(+), 2 deletions(-) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index da41850b46cbd..ed3630068e2ef 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -16,6 +16,7 @@ #include =20 struct page; +struct kmem_cache; =20 #ifdef CONFIG_KMSAN =20 @@ -73,6 +74,44 @@ void kmsan_free_page(struct page *page, unsigned int ord= er); */ void kmsan_copy_page_meta(struct page *dst, struct page *src); =20 +/** + * kmsan_slab_alloc() - Notify KMSAN about a slab allocation. + * @s: slab cache the object belongs to. + * @object: object pointer. + * @flags: GFP flags passed to the allocator. + * + * Depending on cache flags and GFP flags, KMSAN sets up the metadata of t= he + * newly created object, marking it as initialized or uninitialized. + */ +void kmsan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags); + +/** + * kmsan_slab_free() - Notify KMSAN about a slab deallocation. + * @s: slab cache the object belongs to. + * @object: object pointer. + * + * KMSAN marks the freed object as uninitialized. + */ +void kmsan_slab_free(struct kmem_cache *s, void *object); + +/** + * kmsan_kmalloc_large() - Notify KMSAN about a large slab allocation. + * @ptr: object pointer. + * @size: object size. + * @flags: GFP flags passed to the allocator. + * + * Similar to kmsan_slab_alloc(), but for large allocations. + */ +void kmsan_kmalloc_large(const void *ptr, size_t size, gfp_t flags); + +/** + * kmsan_kfree_large() - Notify KMSAN about a large slab deallocation. + * @ptr: object pointer. + * + * Similar to kmsan_slab_free(), but for large allocations. + */ +void kmsan_kfree_large(const void *ptr); + /** * kmsan_map_kernel_range_noflush() - Notify KMSAN about a vmap. * @start: start of vmapped range. @@ -139,6 +178,24 @@ static inline void kmsan_copy_page_meta(struct page *d= st, struct page *src) { } =20 +static inline void kmsan_slab_alloc(struct kmem_cache *s, void *object, + gfp_t flags) +{ +} + +static inline void kmsan_slab_free(struct kmem_cache *s, void *object) +{ +} + +static inline void kmsan_kmalloc_large(const void *ptr, size_t size, + gfp_t flags) +{ +} + +static inline void kmsan_kfree_large(const void *ptr) +{ +} + static inline void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, pgprot_t prot, diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index 5d886df57adca..e7c3ff48ed5cd 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -26,6 +26,86 @@ * skipping effects of functions like memset() inside instrumented code. */ =20 +void kmsan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags) +{ + if (unlikely(object =3D=3D NULL)) + return; + if (!kmsan_enabled || kmsan_in_runtime()) + return; + /* + * There's a ctor or this is an RCU cache - do nothing. The memory + * status hasn't changed since last use. + */ + if (s->ctor || (s->flags & SLAB_TYPESAFE_BY_RCU)) + return; + + kmsan_enter_runtime(); + if (flags & __GFP_ZERO) + kmsan_internal_unpoison_memory(object, s->object_size, + KMSAN_POISON_CHECK); + else + kmsan_internal_poison_memory(object, s->object_size, flags, + KMSAN_POISON_CHECK); + kmsan_leave_runtime(); +} +EXPORT_SYMBOL(kmsan_slab_alloc); + +void kmsan_slab_free(struct kmem_cache *s, void *object) +{ + if (!kmsan_enabled || kmsan_in_runtime()) + return; + + /* RCU slabs could be legally used after free within the RCU period */ + if (unlikely(s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))) + return; + /* + * If there's a constructor, freed memory must remain in the same state + * until the next allocation. We cannot save its state to detect + * use-after-free bugs, instead we just keep it unpoisoned. + */ + if (s->ctor) + return; + kmsan_enter_runtime(); + kmsan_internal_poison_memory(object, s->object_size, GFP_KERNEL, + KMSAN_POISON_CHECK | KMSAN_POISON_FREE); + kmsan_leave_runtime(); +} +EXPORT_SYMBOL(kmsan_slab_free); + +void kmsan_kmalloc_large(const void *ptr, size_t size, gfp_t flags) +{ + if (unlikely(ptr =3D=3D NULL)) + return; + if (!kmsan_enabled || kmsan_in_runtime()) + return; + kmsan_enter_runtime(); + if (flags & __GFP_ZERO) + kmsan_internal_unpoison_memory((void *)ptr, size, + /*checked*/ true); + else + kmsan_internal_poison_memory((void *)ptr, size, flags, + KMSAN_POISON_CHECK); + kmsan_leave_runtime(); +} +EXPORT_SYMBOL(kmsan_kmalloc_large); + +void kmsan_kfree_large(const void *ptr) +{ + struct page *page; + + if (!kmsan_enabled || kmsan_in_runtime()) + return; + kmsan_enter_runtime(); + page =3D virt_to_head_page((void *)ptr); + KMSAN_WARN_ON(ptr !=3D page_address(page)); + kmsan_internal_poison_memory((void *)ptr, + PAGE_SIZE << compound_order(page), + GFP_KERNEL, + KMSAN_POISON_CHECK | KMSAN_POISON_FREE); + kmsan_leave_runtime(); +} +EXPORT_SYMBOL(kmsan_kfree_large); + static unsigned long vmalloc_shadow(unsigned long addr) { return (unsigned long)kmsan_get_metadata((void *)addr, diff --git a/mm/slab.h b/mm/slab.h index c7f2abc2b154c..c2538d856ec45 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -734,6 +734,7 @@ static inline void slab_post_alloc_hook(struct kmem_cac= he *s, memset(p[i], 0, s->object_size); kmemleak_alloc_recursive(p[i], s->object_size, 1, s->flags, flags); + kmsan_slab_alloc(s, p[i], flags); } =20 memcg_slab_post_alloc_hook(s, objcg, flags, size, p); diff --git a/mm/slub.c b/mm/slub.c index 261474092e43e..9b266f6b384b9 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -357,18 +358,28 @@ static void prefetch_freepointer(const struct kmem_ca= che *s, void *object) prefetchw(object + s->offset); } =20 +/* + * When running under KMSAN, get_freepointer_safe() may return an uninitia= lized + * pointer value in the case the current thread loses the race for the next + * memory chunk in the freelist. In that case this_cpu_cmpxchg_double() in + * slab_alloc_node() will fail, so the uninitialized value won't be used, = but + * KMSAN will still check all arguments of cmpxchg because of imperfect + * handling of inline assembly. + * To work around this problem, use kmsan_init() to force initialize the + * return value of get_freepointer_safe(). + */ static inline void *get_freepointer_safe(struct kmem_cache *s, void *objec= t) { unsigned long freepointer_addr; void *p; =20 if (!debug_pagealloc_enabled_static()) - return get_freepointer(s, object); + return kmsan_init(get_freepointer(s, object)); =20 object =3D kasan_reset_tag(object); freepointer_addr =3D (unsigned long)object + s->offset; copy_from_kernel_nofault(&p, (void **)freepointer_addr, sizeof(p)); - return freelist_ptr(s, p, freepointer_addr); + return kmsan_init(freelist_ptr(s, p, freepointer_addr)); } =20 static inline void set_freepointer(struct kmem_cache *s, void *object, voi= d *fp) @@ -1683,6 +1694,7 @@ static inline void *kmalloc_large_node_hook(void *ptr= , size_t size, gfp_t flags) ptr =3D kasan_kmalloc_large(ptr, size, flags); /* As ptr might get tagged, call kmemleak hook after KASAN. */ kmemleak_alloc(ptr, size, 1, flags); + kmsan_kmalloc_large(ptr, size, flags); return ptr; } =20 @@ -1690,12 +1702,14 @@ static __always_inline void kfree_hook(void *x) { kmemleak_free(x); kasan_kfree_large(x); + kmsan_kfree_large(x); } =20 static __always_inline bool slab_free_hook(struct kmem_cache *s, void *x, bool init) { kmemleak_free_recursive(x, s->flags); + kmsan_slab_free(s, x); =20 debug_check_no_locks_freed(x, s->object_size); =20 @@ -3729,6 +3743,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t= flags, size_t size, */ slab_post_alloc_hook(s, objcg, flags, size, p, slab_want_init_on_alloc(flags, s)); + return i; error: slub_put_cpu_ptr(s->cpu_slab); @@ -5910,6 +5925,7 @@ static char *create_unique_id(struct kmem_cache *s) p +=3D sprintf(p, "%07u", s->size); =20 BUG_ON(p > name + ID_STR_LENGTH - 1); + kmsan_unpoison_memory(name, p - name); return name; } =20 @@ -6011,6 +6027,7 @@ static int sysfs_slab_alias(struct kmem_cache *s, con= st char *name) al->name =3D name; al->next =3D alias_list; alias_list =3D al; + kmsan_unpoison_memory(al, sizeof(struct saved_alias)); return 0; } =20 --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90213C433F5 for ; Tue, 29 Mar 2022 12:42:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236604AbiC2MoO (ORCPT ); Tue, 29 Mar 2022 08:44:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236560AbiC2MnI (ORCPT ); Tue, 29 Mar 2022 08:43:08 -0400 Received: from mail-ej1-x64a.google.com (mail-ej1-x64a.google.com [IPv6:2a00:1450:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1CD2122474F for ; Tue, 29 Mar 2022 05:41:23 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id er8-20020a170907738800b006e003254d86so8129538ejc.11 for ; Tue, 29 Mar 2022 05:41:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=KExSZOK6Ak71zPKr5IrSRQ27+lVgS6k5uhCxlphiTtg=; b=tC2AC8qcVBGGwy5YubyQq84+DV0rcKjoONhQrYq3TKU20eKqh0tvDqhPRf7gRqM4PT dJmEH+z3DLtHBAC40BR8tQ/MaqO0WsxWK2QMgj40Hw2S7T7BAU6mtiu18LqGVLCo5/Qo jIKc2qIgz1E97QzbvGKvXcUu6cxEFeypgm1jOEzMJ2+zTDI7QZ7lhF0Ldt76B+O9/+/p 4pJKclD9Afk4fMQo1aDljx1Ws5Se+KObPjS8eyzNIzamBK0W0f/R7pNdSE7W8atZml4H uCyfBqUv6W9GA2MHL83z28IXWM2iPHYU3cZnXPjc+0QxA/mGQCWJHKnuELSvEXq12m1S 7Z0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=KExSZOK6Ak71zPKr5IrSRQ27+lVgS6k5uhCxlphiTtg=; b=Fw1vq3zy6wp+sWl7OMkSP+22fhzbvLMgh3fLJXDBKch/sD5qgZCs9yDKz81vjB/5X/ GeI+c9uSQoW4QOFC1aNtPdZkwFcL+NSli2gNBqOtOKVmeGX8smdJuyO/UAP42u2BJK+I 13rJu3QtDdGi1ym5z/ntdUxpMnyENDzK7FlC9XLSIR52mxqG7fc9KlBKEkCkqKt8RUeo hyAIxQ5C2ezM3vW02BpPO7ZXM6ojSwF75uxpyMwbZ235zI0uIZCyvcixMwbX4bsXoW9b u3qvDMJNQsEdyJD31KEby5BvzWDqYSitnclvwQXUl25f3rgJSUUexYZy1u2m9ufI54J0 zNGg== X-Gm-Message-State: AOAM530D8JRhv1ORXxr45tiA67S4WU6+H389UvwyWCVq4KoRgVAL9KyJ OhqOJGUuj6loXW6wRusnrZHiIK6Bd1Q= X-Google-Smtp-Source: ABdhPJx++M+AfNEUSZZQiWR+2EsjU8nZXkRMWuKEK5h5tMt4uYSC+sCaPadi/60UsvXveKH0DEZLOUoc2uE= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:c092:b0:6cd:f3a1:a11e with SMTP id f18-20020a170906c09200b006cdf3a1a11emr33573510ejz.185.1648557680652; Tue, 29 Mar 2022 05:41:20 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:48 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-20-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 19/48] kmsan: handle task creation and exiting From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Tell KMSAN that a new task is created, so the tool creates a backing metadata structure for that task. Signed-off-by: Alexander Potapenko --- v2: -- move implementation of kmsan_task_create() and kmsan_task_exit() here Link: https://linux-review.googlesource.com/id/I0f41c3a1c7d66f7e14aabcfdfc7= c69addb945805 --- include/linux/kmsan.h | 17 +++++++++++++++++ kernel/exit.c | 2 ++ kernel/fork.c | 2 ++ mm/kmsan/core.c | 10 ++++++++++ mm/kmsan/hooks.c | 19 +++++++++++++++++++ mm/kmsan/kmsan.h | 2 ++ 6 files changed, 52 insertions(+) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index ed3630068e2ef..dca42e0e91991 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -17,6 +17,7 @@ =20 struct page; struct kmem_cache; +struct task_struct; =20 #ifdef CONFIG_KMSAN =20 @@ -43,6 +44,14 @@ struct kmsan_ctx { bool allow_reporting; }; =20 +void kmsan_task_create(struct task_struct *task); + +/** + * kmsan_task_exit() - Notify KMSAN that a task has exited. + * @task: task about to finish. + */ +void kmsan_task_exit(struct task_struct *task); + /** * kmsan_alloc_page() - Notify KMSAN about an alloc_pages() call. * @page: struct page pointer returned by alloc_pages(). @@ -164,6 +173,14 @@ void kmsan_iounmap_page_range(unsigned long start, uns= igned long end); =20 #else =20 +static inline void kmsan_task_create(struct task_struct *task) +{ +} + +static inline void kmsan_task_exit(struct task_struct *task) +{ +} + static inline int kmsan_alloc_page(struct page *page, unsigned int order, gfp_t flags) { diff --git a/kernel/exit.c b/kernel/exit.c index b00a25bb4ab93..15e1bf7fe1fa1 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -59,6 +59,7 @@ #include #include #include +#include #include #include #include @@ -752,6 +753,7 @@ void __noreturn do_exit(long code) force_uaccess_begin(); =20 kcov_task_exit(tsk); + kmsan_task_exit(tsk); =20 coredump_task_exit(tsk); ptrace_event(PTRACE_EVENT_EXIT, code); diff --git a/kernel/fork.c b/kernel/fork.c index f1e89007f2288..f62c51d9cbfb1 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include #include @@ -956,6 +957,7 @@ static struct task_struct *dup_task_struct(struct task_= struct *orig, int node) account_kernel_stack(tsk, 1); =20 kcov_task_init(tsk); + kmsan_task_create(tsk); kmap_local_fork(tsk); =20 #ifdef CONFIG_FAULT_INJECTION diff --git a/mm/kmsan/core.c b/mm/kmsan/core.c index f4196f274e754..8e594361332c6 100644 --- a/mm/kmsan/core.c +++ b/mm/kmsan/core.c @@ -44,6 +44,16 @@ bool kmsan_enabled __read_mostly; */ DEFINE_PER_CPU(struct kmsan_ctx, kmsan_percpu_ctx); =20 +void kmsan_internal_task_create(struct task_struct *task) +{ + struct kmsan_ctx *ctx =3D &task->kmsan_ctx; + + __memset(ctx, 0, sizeof(struct kmsan_ctx)); + ctx->allow_reporting =3D true; + kmsan_internal_unpoison_memory(current_thread_info(), + sizeof(struct thread_info), false); +} + void kmsan_internal_poison_memory(void *address, size_t size, gfp_t flags, unsigned int poison_flags) { diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index e7c3ff48ed5cd..a13e15ef2bfd5 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -26,6 +26,25 @@ * skipping effects of functions like memset() inside instrumented code. */ =20 +void kmsan_task_create(struct task_struct *task) +{ + kmsan_enter_runtime(); + kmsan_internal_task_create(task); + kmsan_leave_runtime(); +} +EXPORT_SYMBOL(kmsan_task_create); + +void kmsan_task_exit(struct task_struct *task) +{ + struct kmsan_ctx *ctx =3D &task->kmsan_ctx; + + if (!kmsan_enabled || kmsan_in_runtime()) + return; + + ctx->allow_reporting =3D false; +} +EXPORT_SYMBOL(kmsan_task_exit); + void kmsan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags) { if (unlikely(object =3D=3D NULL)) diff --git a/mm/kmsan/kmsan.h b/mm/kmsan/kmsan.h index bfe38789950a6..a1b5900ffd97b 100644 --- a/mm/kmsan/kmsan.h +++ b/mm/kmsan/kmsan.h @@ -172,6 +172,8 @@ void kmsan_internal_set_shadow_origin(void *address, si= ze_t size, int b, u32 origin, bool checked); depot_stack_handle_t kmsan_internal_chain_origin(depot_stack_handle_t id); =20 +void kmsan_internal_task_create(struct task_struct *task); + bool kmsan_metadata_is_contiguous(void *addr, size_t size); void kmsan_internal_check_memory(void *addr, size_t size, const void *user= _addr, int reason); --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18311C4332F for ; Tue, 29 Mar 2022 12:42:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236610AbiC2MoS (ORCPT ); Tue, 29 Mar 2022 08:44:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60556 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236586AbiC2MnX (ORCPT ); Tue, 29 Mar 2022 08:43:23 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B7AF5227C4E for ; Tue, 29 Mar 2022 05:41:25 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id d28-20020a50f69c000000b00419125c67f4so10952722edn.17 for ; Tue, 29 Mar 2022 05:41:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=77upEedV9MVWrhKieM+rh+8U4NcJYbcZy6sBqJQFlQA=; b=bnq8hQDOyCgftdNzwXDG/d91U07TnwCybE7fbjRK9l+Km9ccpsbPgpL6A5FRXtFi3h DAZlXoCRZE9ATLpK4lsLef8LJ+7L0QtfFMGiySRhOosaJSPL9aQlMN6TUArQSAlU/IZH X/GEA37JcLkYxodxNzOfq2hhriU8zPP4mQLJIr9rJz3Pgs6TJEbUfKgLtf+9xHvxkToL YGGTqE1B6aNUn6uXtMv9XW7u/kkVLc3AN5E3T7s3MDGrzrHTRuEyq/SdICW+CHxNTwyW QeTG6sbkosyQSzTdvIsKd+EadhvOS0HmjhvbsNcCDuon5xitTIyvmh3aXJ6iYAEciXLJ PgdA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=77upEedV9MVWrhKieM+rh+8U4NcJYbcZy6sBqJQFlQA=; b=5a7WaA9YO/dEssismoO/1ixBhbccyGAPNZrdD34sC4Aap5+fd8CAXjoSvukk1fD78A KAxAV6Qqr5B0Sy1KoluluwkuKWVnBGPud6Q/F4EYIV6+f9Mobqx5DE0DQ0dpz7PU2iH1 d6RgvJCVF3peMBQ4iEmbtUkDWuuOCEbPhhmXi5TLXR7GWCe5Q3IDaAJXoAboW5aTtV15 tZPZKw7sAKxO09atT5QHjX/ZDURiBM7GJQ185L10USU65EB9meqTXo4bLDr5eU5fdCeV xowr7AnTIuMs26Z5KPilqmi2QaVC1im4pEAYeglh0SDpYYDEz20n7amtjyweUlceW98A An4g== X-Gm-Message-State: AOAM531GNvY2MYk3i5Fi2Cs1+wKqhXCwypyw7UAa3VyYNk5ghRcMBTGj centrboI93JuHuZkaPZOJ6uNorpHjvw= X-Google-Smtp-Source: ABdhPJxfRHTi2f4Xo91+bXHbsM1wH3q6jI2ZFHeAyuCAPY6LAlGBC/wE0GczFznCZuQjg0wOJP1fGQHeEA8= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:16ac:b0:6e0:1646:9121 with SMTP id hc44-20020a17090716ac00b006e016469121mr35199102ejc.194.1648557683611; Tue, 29 Mar 2022 05:41:23 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:49 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-21-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 20/48] kmsan: init: call KMSAN initialization routines From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" kmsan_init_shadow() scans the mappings created at boot time and creates metadata pages for those mappings. When the memblock allocator returns pages to pagealloc, we reserve 2/3 of those pages and use them as metadata for the remaining 1/3. Once KMSAN starts, every page allocated by pagealloc has its associated shadow and origin pages. kmsan_initialize() initializes the bookkeeping for init_task and enables KMSAN. Signed-off-by: Alexander Potapenko --- v2: -- move mm/kmsan/init.c and kmsan_memblock_free_pages() to this patch -- print a warning that KMSAN is a debugging tool (per Greg K-H's request) Link: https://linux-review.googlesource.com/id/I7bc53706141275914326df23458= 81ffe0cdd16bd --- include/linux/kmsan.h | 48 +++++++++ init/main.c | 3 + mm/kmsan/Makefile | 3 +- mm/kmsan/init.c | 240 ++++++++++++++++++++++++++++++++++++++++++ mm/kmsan/kmsan.h | 3 + mm/kmsan/shadow.c | 36 +++++++ mm/page_alloc.c | 3 + 7 files changed, 335 insertions(+), 1 deletion(-) create mode 100644 mm/kmsan/init.c diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index dca42e0e91991..a5767c728a46b 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -52,6 +52,40 @@ void kmsan_task_create(struct task_struct *task); */ void kmsan_task_exit(struct task_struct *task); =20 +/** + * kmsan_init_shadow() - Initialize KMSAN shadow at boot time. + * + * Allocate and initialize KMSAN metadata for early allocations. + */ +void __init kmsan_init_shadow(void); + +/** + * kmsan_init_runtime() - Initialize KMSAN state and enable KMSAN. + */ +void __init kmsan_init_runtime(void); + +/** + * kmsan_memblock_free_pages() - handle freeing of memblock pages. + * @page: struct page to free. + * @order: order of @page. + * + * Freed pages are either returned to buddy allocator or held back to be u= sed + * as metadata pages. + */ +bool __init kmsan_memblock_free_pages(struct page *page, unsigned int orde= r); + +/** + * kmsan_task_create() - Initialize KMSAN state for the task. + * @task: task to initialize. + */ +void kmsan_task_create(struct task_struct *task); + +/** + * kmsan_task_exit() - Notify KMSAN that a task has exited. + * @task: task about to finish. + */ +void kmsan_task_exit(struct task_struct *task); + /** * kmsan_alloc_page() - Notify KMSAN about an alloc_pages() call. * @page: struct page pointer returned by alloc_pages(). @@ -173,6 +207,20 @@ void kmsan_iounmap_page_range(unsigned long start, uns= igned long end); =20 #else =20 +static inline void kmsan_init_shadow(void) +{ +} + +static inline void kmsan_init_runtime(void) +{ +} + +static inline bool kmsan_memblock_free_pages(struct page *page, + unsigned int order) +{ + return true; +} + static inline void kmsan_task_create(struct task_struct *task) { } diff --git a/init/main.c b/init/main.c index 65fa2e41a9c09..88be337b54298 100644 --- a/init/main.c +++ b/init/main.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include #include @@ -834,6 +835,7 @@ static void __init mm_init(void) init_mem_debugging_and_hardening(); kfence_alloc_pool(); report_meminit(); + kmsan_init_shadow(); stack_depot_early_init(); mem_init(); mem_init_print_info(); @@ -851,6 +853,7 @@ static void __init mm_init(void) init_espfix_bsp(); /* Should be run after espfix64 is set up. */ pti_init(); + kmsan_init_runtime(); } =20 #ifdef CONFIG_HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET diff --git a/mm/kmsan/Makefile b/mm/kmsan/Makefile index 73b705cbf75b9..f57a956cb1c8b 100644 --- a/mm/kmsan/Makefile +++ b/mm/kmsan/Makefile @@ -1,4 +1,4 @@ -obj-y :=3D core.o instrumentation.o hooks.o report.o shadow.o annotations.o +obj-y :=3D core.o instrumentation.o init.o hooks.o report.o shadow.o annot= ations.o =20 KMSAN_SANITIZE :=3D n KCOV_INSTRUMENT :=3D n @@ -16,6 +16,7 @@ CFLAGS_REMOVE.o =3D $(CC_FLAGS_FTRACE) CFLAGS_annotations.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_core.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_hooks.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) +CFLAGS_init.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_instrumentation.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_report.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_shadow.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) diff --git a/mm/kmsan/init.c b/mm/kmsan/init.c new file mode 100644 index 0000000000000..45757d1390402 --- /dev/null +++ b/mm/kmsan/init.c @@ -0,0 +1,240 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KMSAN initialization routines. + * + * Copyright (C) 2017-2021 Google LLC + * Author: Alexander Potapenko + * + */ + +#include "kmsan.h" + +#include +#include +#include + +#include "../internal.h" + +#define NUM_FUTURE_RANGES 128 +struct start_end_pair { + u64 start, end; +}; + +static struct start_end_pair start_end_pairs[NUM_FUTURE_RANGES] __initdata; +static int future_index __initdata; + +/* + * Record a range of memory for which the metadata pages will be created o= nce + * the page allocator becomes available. + */ +static void __init kmsan_record_future_shadow_range(void *start, void *end) +{ + u64 nstart =3D (u64)start, nend =3D (u64)end, cstart, cend; + bool merged =3D false; + int i; + + KMSAN_WARN_ON(future_index =3D=3D NUM_FUTURE_RANGES); + KMSAN_WARN_ON((nstart >=3D nend) || !nstart || !nend); + nstart =3D ALIGN_DOWN(nstart, PAGE_SIZE); + nend =3D ALIGN(nend, PAGE_SIZE); + + /* + * Scan the existing ranges to see if any of them overlaps with + * [start, end). In that case, merge the two ranges instead of + * creating a new one. + * The number of ranges is less than 20, so there is no need to organize + * them into a more intelligent data structure. + */ + for (i =3D 0; i < future_index; i++) { + cstart =3D start_end_pairs[i].start; + cend =3D start_end_pairs[i].end; + if ((cstart < nstart && cend < nstart) || + (cstart > nend && cend > nend)) + /* ranges are disjoint - do not merge */ + continue; + start_end_pairs[i].start =3D min(nstart, cstart); + start_end_pairs[i].end =3D max(nend, cend); + merged =3D true; + break; + } + if (merged) + return; + start_end_pairs[future_index].start =3D nstart; + start_end_pairs[future_index].end =3D nend; + future_index++; +} + +/* + * Initialize the shadow for existing mappings during kernel initializatio= n. + * These include kernel text/data sections, NODE_DATA and future ranges + * registered while creating other data (e.g. percpu). + * + * Allocations via memblock can be only done before slab is initialized. + */ +void __init kmsan_init_shadow(void) +{ + const size_t nd_size =3D roundup(sizeof(pg_data_t), PAGE_SIZE); + phys_addr_t p_start, p_end; + int nid; + u64 i; + + for_each_reserved_mem_range(i, &p_start, &p_end) + kmsan_record_future_shadow_range(phys_to_virt(p_start), + phys_to_virt(p_end)); + /* Allocate shadow for .data */ + kmsan_record_future_shadow_range(_sdata, _edata); + + for_each_online_node(nid) + kmsan_record_future_shadow_range( + NODE_DATA(nid), (char *)NODE_DATA(nid) + nd_size); + + for (i =3D 0; i < future_index; i++) + kmsan_init_alloc_meta_for_range( + (void *)start_end_pairs[i].start, + (void *)start_end_pairs[i].end); +} +EXPORT_SYMBOL(kmsan_init_shadow); + +struct page_pair { + struct page *shadow, *origin; +}; +static struct page_pair held_back[MAX_ORDER] __initdata; + +/* + * Eager metadata allocation. When the memblock allocator is freeing pages= to + * pagealloc, we use 2/3 of them as metadata for the remaining 1/3. + * We store the pointers to the returned blocks of pages in held_back[] gr= ouped + * by their order: when kmsan_memblock_free_pages() is called for the first + * time with a certain order, it is reserved as a shadow block, for the se= cond + * time - as an origin block. On the third time the incoming block receive= s its + * shadow and origin ranges from the previously saved shadow and origin bl= ocks, + * after which held_back[order] can be used again. + * + * At the very end there may be leftover blocks in held_back[]. They are + * collected later by kmsan_memblock_discard(). + */ +bool kmsan_memblock_free_pages(struct page *page, unsigned int order) +{ + struct page *shadow, *origin; + + if (!held_back[order].shadow) { + held_back[order].shadow =3D page; + return false; + } + if (!held_back[order].origin) { + held_back[order].origin =3D page; + return false; + } + shadow =3D held_back[order].shadow; + origin =3D held_back[order].origin; + kmsan_setup_meta(page, shadow, origin, order); + + held_back[order].shadow =3D NULL; + held_back[order].origin =3D NULL; + return true; +} + +#define MAX_BLOCKS 8 +struct smallstack { + struct page *items[MAX_BLOCKS]; + int index; + int order; +}; + +struct smallstack collect =3D { + .index =3D 0, + .order =3D MAX_ORDER, +}; + +static void smallstack_push(struct smallstack *stack, struct page *pages) +{ + KMSAN_WARN_ON(stack->index =3D=3D MAX_BLOCKS); + stack->items[stack->index] =3D pages; + stack->index++; +} +#undef MAX_BLOCKS + +static struct page *smallstack_pop(struct smallstack *stack) +{ + struct page *ret; + + KMSAN_WARN_ON(stack->index =3D=3D 0); + stack->index--; + ret =3D stack->items[stack->index]; + stack->items[stack->index] =3D NULL; + return ret; +} + +static void do_collection(void) +{ + struct page *page, *shadow, *origin; + + while (collect.index >=3D 3) { + page =3D smallstack_pop(&collect); + shadow =3D smallstack_pop(&collect); + origin =3D smallstack_pop(&collect); + kmsan_setup_meta(page, shadow, origin, collect.order); + __free_pages_core(page, collect.order); + } +} + +static void collect_split(void) +{ + struct smallstack tmp =3D { + .order =3D collect.order - 1, + .index =3D 0, + }; + struct page *page; + + if (!collect.order) + return; + while (collect.index) { + page =3D smallstack_pop(&collect); + smallstack_push(&tmp, &page[0]); + smallstack_push(&tmp, &page[1 << tmp.order]); + } + __memcpy(&collect, &tmp, sizeof(struct smallstack)); +} + +/* + * Memblock is about to go away. Split the page blocks left over in held_b= ack[] + * and return 1/3 of that memory to the system. + */ +static void kmsan_memblock_discard(void) +{ + int i; + + /* + * For each order=3DN: + * - push held_back[N].shadow and .origin to |collect|; + * - while there are >=3D 3 elements in |collect|, do garbage collection: + * - pop 3 ranges from |collect|; + * - use two of them as shadow and origin for the third one; + * - repeat; + * - split each remaining element from |collect| into 2 ranges of + * order=3DN-1, + * - repeat. + */ + collect.order =3D MAX_ORDER - 1; + for (i =3D MAX_ORDER - 1; i >=3D 0; i--) { + if (held_back[i].shadow) + smallstack_push(&collect, held_back[i].shadow); + if (held_back[i].origin) + smallstack_push(&collect, held_back[i].origin); + held_back[i].shadow =3D NULL; + held_back[i].origin =3D NULL; + do_collection(); + collect_split(); + } +} + +void __init kmsan_init_runtime(void) +{ + /* Assuming current is init_task */ + kmsan_internal_task_create(current); + kmsan_memblock_discard(); + pr_info("Starting KernelMemorySanitizer\n"); + pr_info("ATTENTION: KMSAN is a debugging tool! Do not use it on productio= n machines!\n"); + kmsan_enabled =3D true; +} +EXPORT_SYMBOL(kmsan_init_runtime); diff --git a/mm/kmsan/kmsan.h b/mm/kmsan/kmsan.h index a1b5900ffd97b..059f21c39ec1b 100644 --- a/mm/kmsan/kmsan.h +++ b/mm/kmsan/kmsan.h @@ -66,6 +66,7 @@ struct shadow_origin_ptr { struct shadow_origin_ptr kmsan_get_shadow_origin_ptr(void *addr, u64 size, bool store); void *kmsan_get_metadata(void *addr, bool is_origin); +void __init kmsan_init_alloc_meta_for_range(void *start, void *end); =20 enum kmsan_bug_reason { REASON_ANY, @@ -181,5 +182,7 @@ bool kmsan_internal_is_module_addr(void *vaddr); bool kmsan_internal_is_vmalloc_addr(void *addr); =20 struct page *kmsan_vmalloc_to_page_or_null(void *vaddr); +void kmsan_setup_meta(struct page *page, struct page *shadow, + struct page *origin, int order); =20 #endif /* __MM_KMSAN_KMSAN_H */ diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c index 8fe6a5ed05e67..99cb9436eddc6 100644 --- a/mm/kmsan/shadow.c +++ b/mm/kmsan/shadow.c @@ -298,3 +298,39 @@ void kmsan_vmap_pages_range_noflush(unsigned long star= t, unsigned long end, kfree(s_pages); kfree(o_pages); } + +/* Allocate metadata for pages allocated at boot time. */ +void __init kmsan_init_alloc_meta_for_range(void *start, void *end) +{ + struct page *shadow_p, *origin_p; + void *shadow, *origin; + struct page *page; + u64 addr, size; + + start =3D (void *)ALIGN_DOWN((u64)start, PAGE_SIZE); + size =3D ALIGN((u64)end - (u64)start, PAGE_SIZE); + shadow =3D memblock_alloc(size, PAGE_SIZE); + origin =3D memblock_alloc(size, PAGE_SIZE); + for (addr =3D 0; addr < size; addr +=3D PAGE_SIZE) { + page =3D virt_to_page_or_null((char *)start + addr); + shadow_p =3D virt_to_page_or_null((char *)shadow + addr); + set_no_shadow_origin_page(shadow_p); + shadow_page_for(page) =3D shadow_p; + origin_p =3D virt_to_page_or_null((char *)origin + addr); + set_no_shadow_origin_page(origin_p); + origin_page_for(page) =3D origin_p; + } +} + +void kmsan_setup_meta(struct page *page, struct page *shadow, + struct page *origin, int order) +{ + int i; + + for (i =3D 0; i < (1 << order); i++) { + set_no_shadow_origin_page(&shadow[i]); + set_no_shadow_origin_page(&origin[i]); + shadow_page_for(&page[i]) =3D &shadow[i]; + origin_page_for(&page[i]) =3D &origin[i]; + } +} diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 98a066c0a9f63..4237b7290e619 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1751,6 +1751,9 @@ void __init memblock_free_pages(struct page *page, un= signed long pfn, { if (early_page_uninitialised(pfn)) return; + if (!kmsan_memblock_free_pages(page, order)) + /* KMSAN will take care of these pages. */ + return; __free_pages_core(page, order); } =20 --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE979C433EF for ; Tue, 29 Mar 2022 12:43:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234527AbiC2Moj (ORCPT ); Tue, 29 Mar 2022 08:44:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236499AbiC2MnX (ORCPT ); Tue, 29 Mar 2022 08:43:23 -0400 Received: from mail-ej1-x64a.google.com (mail-ej1-x64a.google.com [IPv6:2a00:1450:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3A07229C9E for ; Tue, 29 Mar 2022 05:41:27 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id ga31-20020a1709070c1f00b006cec400422fso8111732ejc.22 for ; Tue, 29 Mar 2022 05:41:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=uZfE98ax1//CK0YNbt0DpMbtwkdW56rBwmCC8QtRUVQ=; b=rze2RjOlA/9+bEmOt3GgL06iHO9tVctaBkBSNuYthH10DOkJoKc11FE48K74+k0ivC Y0nWiNQ4G1OYqS8rf/bOrZUnKPL4+s3Qg8Otbm5Qlrkc06XPathZWsOTt7qxe2+1gGu5 FQenUx3Cf6aNrVRr+SdeQSwMQ5LzNFQJT8QbStroSWij6LrjHD/nihi+tJAX5W+RJUrr HxLXz3xj47nfDdtYPis5g1jTn7KD+ivWymw+OHkntILtKy17lMhGhOuhUrTAddrGgeSQ 8yAh5HjKFp4PVxBIxkWGlL+Kip5Ab0jkaFPz+ndh/En9oJK7jpmUZwOcf0YBR3XglVyQ wshg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=uZfE98ax1//CK0YNbt0DpMbtwkdW56rBwmCC8QtRUVQ=; b=NlInswRov4pFmxbqMKd1AvSRKd7yDjIDfyY/4OvzirryUfz4MznEsVkncWJzIhWITn H/nTGXHCJ7XfH/B2PeUYsmPEcEFS74sPDOoSZBZ6gfDvL67+8ZSb3rXDmaLQGSN3cwj2 ipvL+yF8kj00v6tlbxVIVsRPZk8G98V2EZfz4nwsqhfLDAZXz3pLfkZsbSFpDi8m5coo 6YAM7JxWs6XZRJzmXBkLH5q7pxqmoOZ/+YFMBt+21nqyi/wowqBj4SXVJNmotOS5fb05 QpXWIhjhnJ9N2ck4jTosjbB4w2pFVlJBS9ZMD60yPCt7jXdGxB0Zu5zBvAXEIN8AoEA6 bBPA== X-Gm-Message-State: AOAM532B64svA8DyLREQE/Wp/UZbgGYoUO8D2OVw5wIoxqpP4vF1XmsS H+31GlaI4JZkRlwBDq7UBtMmyqXdUmI= X-Google-Smtp-Source: ABdhPJzxZmXUGeX7ZhTgf8n/xUXjeDK/oOkNktPicPG81/7+K/3c1esguj6n+m5UzDsEoEAM1ZAmk0LXhJs= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a05:6402:657:b0:418:d875:bf12 with SMTP id u23-20020a056402065700b00418d875bf12mr4238058edx.89.1648557686159; Tue, 29 Mar 2022 05:41:26 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:50 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-22-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 21/48] instrumented.h: add KMSAN support From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" To avoid false positives, KMSAN needs to unpoison the data copied from the userspace. To detect infoleaks - check the memory buffer passed to copy_to_user(). Signed-off-by: Alexander Potapenko --- v2: -- move implementation of kmsan_copy_to_user() here Link: https://linux-review.googlesource.com/id/I43e93b9c02709e6be8d222342f1= b044ac8bdbaaf --- include/linux/instrumented.h | 5 ++++- include/linux/kmsan-checks.h | 19 ++++++++++++++++++ mm/kmsan/hooks.c | 38 ++++++++++++++++++++++++++++++++++++ 3 files changed, 61 insertions(+), 1 deletion(-) diff --git a/include/linux/instrumented.h b/include/linux/instrumented.h index ee8f7d17d34f5..c73c1b19e9227 100644 --- a/include/linux/instrumented.h +++ b/include/linux/instrumented.h @@ -2,7 +2,7 @@ =20 /* * This header provides generic wrappers for memory access instrumentation= that - * the compiler cannot emit for: KASAN, KCSAN. + * the compiler cannot emit for: KASAN, KCSAN, KMSAN. */ #ifndef _LINUX_INSTRUMENTED_H #define _LINUX_INSTRUMENTED_H @@ -10,6 +10,7 @@ #include #include #include +#include #include =20 /** @@ -117,6 +118,7 @@ instrument_copy_to_user(void __user *to, const void *fr= om, unsigned long n) { kasan_check_read(from, n); kcsan_check_read(from, n); + kmsan_copy_to_user(to, from, n, 0); } =20 /** @@ -151,6 +153,7 @@ static __always_inline void instrument_copy_from_user_after(const void *to, const void __user *from, unsigned long n, unsigned long left) { + kmsan_unpoison_memory(to, n - left); } =20 #endif /* _LINUX_INSTRUMENTED_H */ diff --git a/include/linux/kmsan-checks.h b/include/linux/kmsan-checks.h index ecd8336190fc0..aabaf1ba7c251 100644 --- a/include/linux/kmsan-checks.h +++ b/include/linux/kmsan-checks.h @@ -84,6 +84,21 @@ void kmsan_unpoison_memory(const void *address, size_t s= ize); */ void kmsan_check_memory(const void *address, size_t size); =20 +/** + * kmsan_copy_to_user() - Notify KMSAN about a data transfer to userspace. + * @to: destination address in the userspace. + * @from: source address in the kernel. + * @to_copy: number of bytes to copy. + * @left: number of bytes not copied. + * + * If this is a real userspace data transfer, KMSAN checks the bytes that = were + * actually copied to ensure there was no information leak. If @to belongs= to + * the kernel space (which is possible for compat syscalls), KMSAN just co= pies + * the metadata. + */ +void kmsan_copy_to_user(void __user *to, const void *from, size_t to_copy, + size_t left); + #else =20 #define kmsan_init(value) (value) @@ -98,6 +113,10 @@ static inline void kmsan_unpoison_memory(const void *ad= dress, size_t size) static inline void kmsan_check_memory(const void *address, size_t size) { } +static inline void kmsan_copy_to_user(void __user *to, const void *from, + size_t to_copy, size_t left) +{ +} =20 #endif =20 diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index a13e15ef2bfd5..365eedcb08953 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -212,6 +212,44 @@ void kmsan_iounmap_page_range(unsigned long start, uns= igned long end) } EXPORT_SYMBOL(kmsan_iounmap_page_range); =20 +void kmsan_copy_to_user(void __user *to, const void *from, size_t to_copy, + size_t left) +{ + unsigned long ua_flags; + + if (!kmsan_enabled || kmsan_in_runtime()) + return; + /* + * At this point we've copied the memory already. It's hard to check it + * before copying, as the size of actually copied buffer is unknown. + */ + + /* copy_to_user() may copy zero bytes. No need to check. */ + if (!to_copy) + return; + /* Or maybe copy_to_user() failed to copy anything. */ + if (to_copy <=3D left) + return; + + ua_flags =3D user_access_save(); + if ((u64)to < TASK_SIZE) { + /* This is a user memory access, check it. */ + kmsan_internal_check_memory((void *)from, to_copy - left, to, + REASON_COPY_TO_USER); + user_access_restore(ua_flags); + return; + } + /* Otherwise this is a kernel memory access. This happens when a compat + * syscall passes an argument allocated on the kernel stack to a real + * syscall. + * Don't check anything, just copy the shadow of the copied bytes. + */ + kmsan_internal_memmove_metadata((void *)to, (void *)from, + to_copy - left); + user_access_restore(ua_flags); +} +EXPORT_SYMBOL(kmsan_copy_to_user); + /* Functions from kmsan-checks.h follow. */ void kmsan_poison_memory(const void *address, size_t size, gfp_t flags) { --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EA4D8C433EF for ; Tue, 29 Mar 2022 12:44:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236686AbiC2Mop (ORCPT ); Tue, 29 Mar 2022 08:44:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236609AbiC2Mni (ORCPT ); Tue, 29 Mar 2022 08:43:38 -0400 Received: from mail-lf1-x149.google.com (mail-lf1-x149.google.com [IPv6:2a00:1450:4864:20::149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F103222C6F0 for ; Tue, 29 Mar 2022 05:41:30 -0700 (PDT) Received: by mail-lf1-x149.google.com with SMTP id bq6-20020a056512150600b0044840cccf4bso5250778lfb.1 for ; Tue, 29 Mar 2022 05:41:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=BAzeUERAw6yLQmtyQnYKjc6/ZWWpRBj0mGa3aEgUqwY=; b=ZXTRoZrgutkv7II3RgLRe7BIf7v6I4j8hJJZqYQ4g8PulMF1nWo8ubAU21o9zCo6og 7XBKKviqr7NMytXoYSl85SE+bb3+8jznUOcFKa7H4EfRJL1oCEVy4UXGzDb0BQ4KlMwY EBXkG4Uwv5g0U86kh/wZsWl0ZxVsJugX71jrS1cq2SiiKeYxM2S9e9CzF0yqfyAB7oMi T4oGblkIF/ayb7nfMcBDRVAt1sbzaznoywLIxzm1ieHGWctjb5MdaLEykaspo2SdhHvF 4nzwX4TkXzi+AOfJ+V1Cf2u4NZt6lo6PUhaz3zGGMcsWgjPIXLv2JnNVaViWv1sI8XVk WNew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=BAzeUERAw6yLQmtyQnYKjc6/ZWWpRBj0mGa3aEgUqwY=; b=tN4aIXVmcTTqW8JUnwEZvSWn3metoK8JIt3ySRO73c70gkWWd6GlQqIlEZZe5vdPsq 9wT+LGY4CkKs8HGFGrqZkOqBSIWVi++xk7lX439tjPS3h8+P5lHfR1ByCrtPMgRLEOlM /BU+/ZM7zRlYypMstWiNRojtU1ix0lK0rUsaYMlUHOkxnHfH4kL0yabvDFYUYjipJM41 C9OLZBzlnTsH1rPX76txOpLmBCNrtw11Ej3pkW1haQDnCcbD5sSxM3LTR2KTPNy6xBSv 22dJv9/p2fvsXefgWmb49v1HbH+LCbwYO40yDDD1ZmUlhQex15k+tRJ+y23K3yD2oVpC b0+Q== X-Gm-Message-State: AOAM531RnS7E2ovfAh3/G2nBmRjAY/WPlkTGxVc2WYM4f5mr4iYfRTP5 Ph1faAiTd93sZzoGowEJdeETepaayxw= X-Google-Smtp-Source: ABdhPJx1CLANrsI9lz+hySXN8o14iMay2HDGrWuM+l9vsgDilsmJEoz0jnKi7yedCbB7BcBmZTRdVovSVm0= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a19:e05c:0:b0:44a:15b9:68b9 with SMTP id g28-20020a19e05c000000b0044a15b968b9mr2466190lfj.575.1648557688677; Tue, 29 Mar 2022 05:41:28 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:51 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-23-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 22/48] kmsan: unpoison @tlb in arch_tlb_gather_mmu() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This is a hack to reduce stackdepot pressure. struct mmu_gather contains 7 1-bit fields packed into a 32-bit unsigned int value. The remaining 25 bits remain uninitialized and are never used, but KMSAN updates the origin for them in zap_pXX_range() in mm/memory.c, thus creating very long origin chains. This is technically correct, but consumes too much memory. Unpoisoning the whole structure will prevent creating such chains. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I76abee411b8323acfdbc29bc3a6= 0dca8cff2de77 --- mm/mmu_gather.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c index afb7185ffdc45..2f3821268b311 100644 --- a/mm/mmu_gather.c +++ b/mm/mmu_gather.c @@ -1,6 +1,7 @@ #include #include #include +#include #include #include #include @@ -253,6 +254,15 @@ void tlb_flush_mmu(struct mmu_gather *tlb) static void __tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm) { + /* + * struct mmu_gather contains 7 1-bit fields packed into a 32-bit + * unsigned int value. The remaining 25 bits remain uninitialized + * and are never used, but KMSAN updates the origin for them in + * zap_pXX_range() in mm/memory.c, thus creating very long origin + * chains. This is technically correct, but consumes too much memory. + * Unpoisoning the whole structure will prevent creating such chains. + */ + kmsan_unpoison_memory(tlb, sizeof(*tlb)); tlb->mm =3D mm; tlb->fullmm =3D fullmm; =20 --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 96DC7C433EF for ; Tue, 29 Mar 2022 12:43:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236553AbiC2Moy (ORCPT ); Tue, 29 Mar 2022 08:44:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236621AbiC2Mni (ORCPT ); Tue, 29 Mar 2022 08:43:38 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6541622F3E8 for ; Tue, 29 Mar 2022 05:41:32 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id zd21-20020a17090698d500b006df778721f7so8057288ejb.3 for ; Tue, 29 Mar 2022 05:41:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=1qZ36eD+kaWsJnQ8auEpiZ1rW+bfAeskKwd1x/lbm8E=; b=Rcnu0ftYaviimZCkKchXhLzv4Y9UohEdLtNeE87+i4g2lUAFIdAHcrYb6VunYkRO45 0OlJa6TS8CgDxoAQ27qSa4/PMQF86Knx0tCOfbCLtEU24OihmG2+K8/Xo6wOyhahHFhr JmmVtHN25QPgPBe0WNM/XDHAv3tqmwVnno70IommFUD2T5T0L84175cKoN/YlYtKFc+X aXelqCm+GznSbMRU3j6C+wZrte+7TkDPvPe87ccCSj4gMUczWPnDSQWiPrlld8xpNWhg l9rwkEHT/9p/eJIqOK330aaMwuIxjN+oh9bbey1ho0lgCeKyd6Q+1EnhAOJQA5Oa789Z LNHQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=1qZ36eD+kaWsJnQ8auEpiZ1rW+bfAeskKwd1x/lbm8E=; b=ObCtRoRrbGSJHdfXcb9Nb9V8gnwG6ga+QasbxPutoVaeoxbJoXpdw4MCdH6HlgYKdw WjSQmnRE30M1dgI1kQzZ/IJHKO6iY4547AF0UAPL4hwnSDYq3s+cKHhhNhE8qwUMBp78 QC4Kct217fWZnoucZ1xSvQunVkQo5iMFBQBjE/3xYODqPujA4OCT0fbCEd/6ynvNd272 o0+t5vS8p0hfDZFJfz1VfloAYN8KSb7lS0DuaeKN9a4WEx7MabhOngiscjmTqn0S0bPt WbuyZoogB+ocvIJVLok6y52nPFYqkeAp+ZMG/MsQoCQvN6UO2kmluSkFmSJIGHftAddH xOsw== X-Gm-Message-State: AOAM531IIHT6YDC9G6qTX0dYGShXyLBy//PJIQz7JYbBJgXbfX0S31Tm op3sxzjW8n0WAZmvDQ0c7KgepgihDMc= X-Google-Smtp-Source: ABdhPJwlWxNKietnPeU8wgYIdm3etjxbDw8r9KenX80watwB3MiI5sKIPJR8qvY4K4Ud6K1EwuvorSt75Fw= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a05:6402:6c2:b0:419:1a14:8fb2 with SMTP id n2-20020a05640206c200b004191a148fb2mr4326522edy.415.1648557691238; Tue, 29 Mar 2022 05:41:31 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:52 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-24-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 23/48] kmsan: add iomap support From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Functions from lib/iomap.c interact with hardware, so KMSAN must ensure that: - every read function returns an initialized value - every write function checks values before sending them to hardware. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I45527599f09090aca046dfe1a26= df453adab100d --- lib/iomap.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/lib/iomap.c b/lib/iomap.c index fbaa3e8f19d6c..bdda1a42771b2 100644 --- a/lib/iomap.c +++ b/lib/iomap.c @@ -6,6 +6,7 @@ */ #include #include +#include =20 #include =20 @@ -70,26 +71,31 @@ static void bad_io_access(unsigned long port, const cha= r *access) #define mmio_read64be(addr) swab64(readq(addr)) #endif =20 +__no_sanitize_memory unsigned int ioread8(const void __iomem *addr) { IO_COND(addr, return inb(port), return readb(addr)); return 0xff; } +__no_sanitize_memory unsigned int ioread16(const void __iomem *addr) { IO_COND(addr, return inw(port), return readw(addr)); return 0xffff; } +__no_sanitize_memory unsigned int ioread16be(const void __iomem *addr) { IO_COND(addr, return pio_read16be(port), return mmio_read16be(addr)); return 0xffff; } +__no_sanitize_memory unsigned int ioread32(const void __iomem *addr) { IO_COND(addr, return inl(port), return readl(addr)); return 0xffffffff; } +__no_sanitize_memory unsigned int ioread32be(const void __iomem *addr) { IO_COND(addr, return pio_read32be(port), return mmio_read32be(addr)); @@ -142,18 +148,21 @@ static u64 pio_read64be_hi_lo(unsigned long port) return lo | (hi << 32); } =20 +__no_sanitize_memory u64 ioread64_lo_hi(const void __iomem *addr) { IO_COND(addr, return pio_read64_lo_hi(port), return readq(addr)); return 0xffffffffffffffffULL; } =20 +__no_sanitize_memory u64 ioread64_hi_lo(const void __iomem *addr) { IO_COND(addr, return pio_read64_hi_lo(port), return readq(addr)); return 0xffffffffffffffffULL; } =20 +__no_sanitize_memory u64 ioread64be_lo_hi(const void __iomem *addr) { IO_COND(addr, return pio_read64be_lo_hi(port), @@ -161,6 +170,7 @@ u64 ioread64be_lo_hi(const void __iomem *addr) return 0xffffffffffffffffULL; } =20 +__no_sanitize_memory u64 ioread64be_hi_lo(const void __iomem *addr) { IO_COND(addr, return pio_read64be_hi_lo(port), @@ -188,22 +198,32 @@ EXPORT_SYMBOL(ioread64be_hi_lo); =20 void iowrite8(u8 val, void __iomem *addr) { + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(&val, sizeof(val)); IO_COND(addr, outb(val,port), writeb(val, addr)); } void iowrite16(u16 val, void __iomem *addr) { + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(&val, sizeof(val)); IO_COND(addr, outw(val,port), writew(val, addr)); } void iowrite16be(u16 val, void __iomem *addr) { + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(&val, sizeof(val)); IO_COND(addr, pio_write16be(val,port), mmio_write16be(val, addr)); } void iowrite32(u32 val, void __iomem *addr) { + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(&val, sizeof(val)); IO_COND(addr, outl(val,port), writel(val, addr)); } void iowrite32be(u32 val, void __iomem *addr) { + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(&val, sizeof(val)); IO_COND(addr, pio_write32be(val,port), mmio_write32be(val, addr)); } EXPORT_SYMBOL(iowrite8); @@ -239,24 +259,32 @@ static void pio_write64be_hi_lo(u64 val, unsigned lon= g port) =20 void iowrite64_lo_hi(u64 val, void __iomem *addr) { + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(&val, sizeof(val)); IO_COND(addr, pio_write64_lo_hi(val, port), writeq(val, addr)); } =20 void iowrite64_hi_lo(u64 val, void __iomem *addr) { + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(&val, sizeof(val)); IO_COND(addr, pio_write64_hi_lo(val, port), writeq(val, addr)); } =20 void iowrite64be_lo_hi(u64 val, void __iomem *addr) { + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(&val, sizeof(val)); IO_COND(addr, pio_write64be_lo_hi(val, port), mmio_write64be(val, addr)); } =20 void iowrite64be_hi_lo(u64 val, void __iomem *addr) { + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(&val, sizeof(val)); IO_COND(addr, pio_write64be_hi_lo(val, port), mmio_write64be(val, addr)); } @@ -328,14 +356,20 @@ static inline void mmio_outsl(void __iomem *addr, con= st u32 *src, int count) void ioread8_rep(const void __iomem *addr, void *dst, unsigned long count) { IO_COND(addr, insb(port,dst,count), mmio_insb(addr, dst, count)); + /* KMSAN must treat values read from devices as initialized. */ + kmsan_unpoison_memory(dst, count); } void ioread16_rep(const void __iomem *addr, void *dst, unsigned long count) { IO_COND(addr, insw(port,dst,count), mmio_insw(addr, dst, count)); + /* KMSAN must treat values read from devices as initialized. */ + kmsan_unpoison_memory(dst, count * 2); } void ioread32_rep(const void __iomem *addr, void *dst, unsigned long count) { IO_COND(addr, insl(port,dst,count), mmio_insl(addr, dst, count)); + /* KMSAN must treat values read from devices as initialized. */ + kmsan_unpoison_memory(dst, count * 4); } EXPORT_SYMBOL(ioread8_rep); EXPORT_SYMBOL(ioread16_rep); @@ -343,14 +377,20 @@ EXPORT_SYMBOL(ioread32_rep); =20 void iowrite8_rep(void __iomem *addr, const void *src, unsigned long count) { + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(src, count); IO_COND(addr, outsb(port, src, count), mmio_outsb(addr, src, count)); } void iowrite16_rep(void __iomem *addr, const void *src, unsigned long coun= t) { + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(src, count * 2); IO_COND(addr, outsw(port, src, count), mmio_outsw(addr, src, count)); } void iowrite32_rep(void __iomem *addr, const void *src, unsigned long coun= t) { + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(src, count * 4); IO_COND(addr, outsl(port, src,count), mmio_outsl(addr, src, count)); } EXPORT_SYMBOL(iowrite8_rep); --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76713C433F5 for ; Tue, 29 Mar 2022 12:43:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236631AbiC2Mo4 (ORCPT ); Tue, 29 Mar 2022 08:44:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236549AbiC2Mnz (ORCPT ); Tue, 29 Mar 2022 08:43:55 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63D8622BD7E for ; Tue, 29 Mar 2022 05:41:35 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id h22-20020a1709060f5600b006b11a2d3dcfso8125893ejj.4 for ; Tue, 29 Mar 2022 05:41:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=lsB3lK0aPu+8HWqdJ6/yM1q11PTSMtec/DSdWJ9paXQ=; b=Y2VTXLEBSbXPLu5uhbEKKqB5AO9gIHu9jp/jSny35LuwmGZ+c+hEVtLUWlhSpPVc22 TxOvlY9Yoi7apyfs9Ow6Y9SD8BcLDmBd8zCFsJWqvD1r8+3P/s4FNpxe3VpbUFeGmI1r M2s3smZ8WKAQfLh/zIYUs4yveEnHKHAWaMCHAYZM2EsQtnTEE9sa+vHBJ2c8G01CB99w h+wWzCDc56ZhTweuBlI3h1rdzZJaGibE55vpeLcLzYyMpMH4Nsc8X53WytkodgNs2hJR 4GEA20pYgJcw96lcVe50mTK7DAkc1u2xxRnNcQ3uEduO2cpHhhWmbgpFaG8L9ULcZ04m Xtfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=lsB3lK0aPu+8HWqdJ6/yM1q11PTSMtec/DSdWJ9paXQ=; b=CylNMxgPEKIL2TWBbVn3Lz9Ru+EXRzHKoqCV/5KmeWhgpzrc61x8LXta/0gR59MHZX HK5MTz6LY4ZnNgS7G8wSKhB1+aJ418oEoFMDcN/k1KleFoMudkZqSBbsHIOO4ufJl9Dt Y0Zm/ZRcDFpj6TcyZW4uqX7IWNgfRW4TBBpq9w2DYZ+tmbzvIgjW2sIAB/rkc+LWMHrf XVnZKfRQAQrm6LlvYFmBl9+WnsB7xJ6DbL1f6HBltKjGqTgsbG5Di++DOYvRx2ISTh5V gWjeY8je6ajGhVHHUC60aVBO5qFHlR8FiygNshrpiaw2fuKU7iTFyYlc5TuQlQh7UULp icbg== X-Gm-Message-State: AOAM533q3DnRRvPZTU181oA/EQpk5Wi6dKv9vCVUXvUFjmVd3yvX1TUH MVa99EMTFtSnVHxkOHjlIoykHpsYFnY= X-Google-Smtp-Source: ABdhPJxMT7rO1P57N71ZmYbIOwRuf4arJokbiW9dyI3uwrKnuskidOOGFTc8VrM1ts4i4n0XHHumgcOFJA8= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:1ec3:b0:6cf:d118:59e2 with SMTP id m3-20020a1709061ec300b006cfd11859e2mr34473282ejj.767.1648557693731; Tue, 29 Mar 2022 05:41:33 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:53 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-25-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 24/48] Input: libps2: mark data received in __ps2_command() as initialized From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KMSAN does not know that the device initializes certain bytes in ps2dev->cmdbuf. Call kmsan_unpoison_memory() to explicitly mark them as initialized. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I2d26f6baa45271d37320d3f4a52= 8c39cb7e545f0 --- drivers/input/serio/libps2.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c index 250e213cc80c6..3e19344eda93c 100644 --- a/drivers/input/serio/libps2.c +++ b/drivers/input/serio/libps2.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -294,9 +295,11 @@ int __ps2_command(struct ps2dev *ps2dev, u8 *param, un= signed int command) =20 serio_pause_rx(ps2dev->serio); =20 - if (param) + if (param) { for (i =3D 0; i < receive; i++) param[i] =3D ps2dev->cmdbuf[(receive - 1) - i]; + kmsan_unpoison_memory(param, receive); + } =20 if (ps2dev->cmdcnt && (command !=3D PS2_CMD_RESET_BAT || ps2dev->cmdcnt !=3D 1)) { --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A45CC433F5 for ; Tue, 29 Mar 2022 12:43:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236636AbiC2MpG (ORCPT ); Tue, 29 Mar 2022 08:45:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35256 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236236AbiC2Mn4 (ORCPT ); Tue, 29 Mar 2022 08:43:56 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3799232D1A for ; Tue, 29 Mar 2022 05:41:37 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id i22-20020a508716000000b0041908045af3so10873263edb.3 for ; Tue, 29 Mar 2022 05:41:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=kipmwjlnp7WROf90XDDYlpUL7HaVlKXhrZy7k38OjBk=; b=swBA+8/qBkvXXmxorMDqi6vUFeeZi3bN3raFZeA6IFlfLjInfXV+4iwKXj0XrLGgoC JQ7bqpVR4Aq6pLKUjKxxUVfZRxlPvshj9+PPkWZx9bHUxFIXGZ9Mq+01KZGeGQ12fXDH hkgtDJsBgTYCvyqeM4bo+uyBanKqRZjXekJyVVND/ULHYZSnwRSRhS0uDUYE2S32ihmM dc66EcjcYlTDsHsqTVtcqfQaGQIfQQjOUGnIkCiRunD8AdG9BsQx+9zQnqfMk6znpSBZ VdRLWG/DUzMLxudxXPvP6Z5TI95jhTKxcLr2iFonvlWLmVR44+5uS324vfekljJlpbJr pDqA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=kipmwjlnp7WROf90XDDYlpUL7HaVlKXhrZy7k38OjBk=; b=PgLutgZqEZx+aCU6ZPsZnjLJaMz59WckHalfk/ix8DmFb+DUOrK5MFuesN9ogP0Tg7 lpiJ1ChW/UYgTEFwkIJGaQzdIjHv2vXKvc6uOLvmgugJMpcZQXITDum1tB/O7CFolqqA aB0RFVmyzqdu08WV89QUFe1OvT+/l2iYSDsvHqWe7YewyUaBu1XnGvz1QDjboKAtslL9 PhbajaUiRpQmxV7UN0Q4ixYcFF/0y7qAbHdRPWe3yYzEYFsPA7H5T6to32W5IK8k5vK1 NwWgrLbwdyLUIdJn4XAoI506+WLw+lDVCJ+Kclh2LralSdYLP8uDxNgXkM1LsmCJW7RW JxiA== X-Gm-Message-State: AOAM533LD0P5tdEWwhh4fpIPtZ9kVM4zS3TKhUscZKCxcHAcSZ+Q4NjB 8xjZ+DxOujIrVqKbCUB571Uc3kdC4wE= X-Google-Smtp-Source: ABdhPJxtsqcpedBaD+pU00yaPAgOV5o7+L5K3nWzYJ9Q8ykrvoNlGaLEfr4A4ubrOrFSZ9FsAwRvka1gJuQ= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:1623:b0:6df:c9da:a6a8 with SMTP id hb35-20020a170907162300b006dfc9daa6a8mr33823933ejc.303.1648557696191; Tue, 29 Mar 2022 05:41:36 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:54 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-26-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 25/48] kmsan: dma: unpoison DMA mappings From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KMSAN doesn't know about DMA memory writes performed by devices. We unpoison such memory when it's mapped to avoid false positive reports. Signed-off-by: Alexander Potapenko --- v2: -- move implementation of kmsan_handle_dma() and kmsan_handle_dma_sg() here Link: https://linux-review.googlesource.com/id/Ia162dc4c5a92e74d4686c1be32a= 4dfeffc5c32cd --- include/linux/kmsan.h | 41 +++++++++++++++++++++++++++++ kernel/dma/mapping.c | 9 ++++--- mm/kmsan/hooks.c | 61 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 108 insertions(+), 3 deletions(-) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index a5767c728a46b..d8667161a10c8 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -9,6 +9,7 @@ #ifndef _LINUX_KMSAN_H #define _LINUX_KMSAN_H =20 +#include #include #include #include @@ -18,6 +19,7 @@ struct page; struct kmem_cache; struct task_struct; +struct scatterlist; =20 #ifdef CONFIG_KMSAN =20 @@ -205,6 +207,35 @@ void kmsan_ioremap_page_range(unsigned long addr, unsi= gned long end, */ void kmsan_iounmap_page_range(unsigned long start, unsigned long end); =20 +/** + * kmsan_handle_dma() - Handle a DMA data transfer. + * @page: first page of the buffer. + * @offset: offset of the buffer within the first page. + * @size: buffer size. + * @dir: one of possible dma_data_direction values. + * + * Depending on @direction, KMSAN: + * * checks the buffer, if it is copied to device; + * * initializes the buffer, if it is copied from device; + * * does both, if this is a DMA_BIDIRECTIONAL transfer. + */ +void kmsan_handle_dma(struct page *page, size_t offset, size_t size, + enum dma_data_direction dir); + +/** + * kmsan_handle_dma_sg() - Handle a DMA transfer using scatterlist. + * @sg: scatterlist holding DMA buffers. + * @nents: number of scatterlist entries. + * @dir: one of possible dma_data_direction values. + * + * Depending on @direction, KMSAN: + * * checks the buffers in the scatterlist, if they are copied to device; + * * initializes the buffers, if they are copied from device; + * * does both, if this is a DMA_BIDIRECTIONAL transfer. + */ +void kmsan_handle_dma_sg(struct scatterlist *sg, int nents, + enum dma_data_direction dir); + #else =20 static inline void kmsan_init_shadow(void) @@ -287,6 +318,16 @@ static inline void kmsan_iounmap_page_range(unsigned l= ong start, { } =20 +static inline void kmsan_handle_dma(struct page *page, size_t offset, + size_t size, enum dma_data_direction dir) +{ +} + +static inline void kmsan_handle_dma_sg(struct scatterlist *sg, int nents, + enum dma_data_direction dir) +{ +} + #endif =20 #endif /* _LINUX_KMSAN_H */ diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 9478eccd1c8e6..0560080813761 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -156,6 +156,7 @@ dma_addr_t dma_map_page_attrs(struct device *dev, struc= t page *page, addr =3D dma_direct_map_page(dev, page, offset, size, dir, attrs); else addr =3D ops->map_page(dev, page, offset, size, dir, attrs); + kmsan_handle_dma(page, offset, size, dir); debug_dma_map_page(dev, page, offset, size, dir, addr, attrs); =20 return addr; @@ -194,11 +195,13 @@ static int __dma_map_sg_attrs(struct device *dev, str= uct scatterlist *sg, else ents =3D ops->map_sg(dev, sg, nents, dir, attrs); =20 - if (ents > 0) + if (ents > 0) { + kmsan_handle_dma_sg(sg, nents, dir); debug_dma_map_sg(dev, sg, nents, ents, dir, attrs); - else if (WARN_ON_ONCE(ents !=3D -EINVAL && ents !=3D -ENOMEM && - ents !=3D -EIO)) + } else if (WARN_ON_ONCE(ents !=3D -EINVAL && ents !=3D -ENOMEM && + ents !=3D -EIO)) { return -EIO; + } =20 return ents; } diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index 365eedcb08953..cc3465bd69754 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -10,9 +10,11 @@ */ =20 #include +#include #include #include #include +#include #include #include =20 @@ -250,6 +252,65 @@ void kmsan_copy_to_user(void __user *to, const void *f= rom, size_t to_copy, } EXPORT_SYMBOL(kmsan_copy_to_user); =20 +static void kmsan_handle_dma_page(const void *addr, size_t size, + enum dma_data_direction dir) +{ + switch (dir) { + case DMA_BIDIRECTIONAL: + kmsan_internal_check_memory((void *)addr, size, /*user_addr*/ 0, + REASON_ANY); + kmsan_internal_unpoison_memory((void *)addr, size, + /*checked*/ false); + break; + case DMA_TO_DEVICE: + kmsan_internal_check_memory((void *)addr, size, /*user_addr*/ 0, + REASON_ANY); + break; + case DMA_FROM_DEVICE: + kmsan_internal_unpoison_memory((void *)addr, size, + /*checked*/ false); + break; + case DMA_NONE: + break; + } +} + +/* Helper function to handle DMA data transfers. */ +void kmsan_handle_dma(struct page *page, size_t offset, size_t size, + enum dma_data_direction dir) +{ + u64 page_offset, to_go, addr; + + if (PageHighMem(page)) + return; + addr =3D (u64)page_address(page) + offset; + /* + * The kernel may occasionally give us adjacent DMA pages not belonging + * to the same allocation. Process them separately to avoid triggering + * internal KMSAN checks. + */ + while (size > 0) { + page_offset =3D addr % PAGE_SIZE; + to_go =3D min(PAGE_SIZE - page_offset, (u64)size); + kmsan_handle_dma_page((void *)addr, to_go, dir); + addr +=3D to_go; + size -=3D to_go; + } +} +EXPORT_SYMBOL(kmsan_handle_dma); + +void kmsan_handle_dma_sg(struct scatterlist *sg, int nents, + enum dma_data_direction dir) +{ + struct scatterlist *item; + int i; + + for_each_sg(sg, item, nents, i) + kmsan_handle_dma(sg_page(item), item->offset, item->length, + dir); +} +EXPORT_SYMBOL(kmsan_handle_dma_sg); + /* Functions from kmsan-checks.h follow. */ void kmsan_poison_memory(const void *address, size_t size, gfp_t flags) { --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBE7BC433EF for ; Tue, 29 Mar 2022 12:43:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236336AbiC2MpR (ORCPT ); Tue, 29 Mar 2022 08:45:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236498AbiC2Mn5 (ORCPT ); Tue, 29 Mar 2022 08:43:57 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8DBD3235747 for ; Tue, 29 Mar 2022 05:41:40 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id x1-20020a50f181000000b00418f6d4bccbso10995002edl.12 for ; Tue, 29 Mar 2022 05:41:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=Eb/Abij6XQ3iqbkwUGDaEHK0fSpQBifUF5HLZH6JcRc=; b=Krkj/S1jh5/H05+jCH+MSNkam2il8xetzlLh3mofzSw3z1EUZVLwTavHzuR07R13in fg9//+1CujBKky+Yg98dxF0i9pubcLdyg1zZweQ1XjNQleJiDN/XoHbConhYKPEsItrW Hqor3bLi18aLxBGMha4/9ZF65JCN2E/xs869FWNbVFPNZlCCTsmL0+sn19SYqkD+nycO 8yokw7MAHVM6QSu96rl3jBfgqKH9wHHao396wVZYsEKnozljUrrFpvS6mVwzvzPs2PCk rZme07+nb4Ir4EhmUhbog2UgvqaC31UAfTNt+DsOKVK0oofUTAwJkiObvGLB48vzpwDI J6HA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=Eb/Abij6XQ3iqbkwUGDaEHK0fSpQBifUF5HLZH6JcRc=; b=V2agB6d9nu81CjHCH4v47slIiQhjMt01mVriRBkrxR9TZDra1lkW+WJcry5xmIkfiJ cl4J54L+qIDcHahRRwu9D+R+8xScL7nkQX6WOk1OPfWUMX/mah5mYHD3HmXrdgznrekk hEttfQTY24Jnyg8RqKpG5nD3EATw6IghplAPZwirTh3EiizIbH0ENmL5kMw1aVc8B/vH mqu+1OACkuroiGZK2wWYXDKTeYD3Bdo9QYJvhygnmdduzZ93rDQKio4LD2E41GKXMydq lk25lV+dFbls/h0JorgY4CQpxCu/jCCA6Unn0kEAMDshGwm8+BfPCUK3NfkKng8zEgtD OhIA== X-Gm-Message-State: AOAM5322Ig0QvMqHVogFUTlQOloIskkh8jOWsNehS2AptXcSrXrwJMb1 985Hq/wZoVSAGOLCjfUAGn61/HINhLw= X-Google-Smtp-Source: ABdhPJxL1GeaEMAohn+FBay8BfgBp3WhpguNB4XCKO3e3e1LP1mlhUbZL/tt/mlN/CXlhJVrae+cgzEdiVU= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:7f09:b0:6e0:395d:cc88 with SMTP id qf9-20020a1709077f0900b006e0395dcc88mr34433043ejc.566.1648557698741; Tue, 29 Mar 2022 05:41:38 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:55 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-27-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 26/48] kmsan: virtio: check/unpoison scatterlist in vring_map_one_sg() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" If vring doesn't use the DMA API, KMSAN is unable to tell whether the memory is initialized by hardware. Explicitly call kmsan_handle_dma() from vring_map_one_sg() in this case to prevent false positives. Signed-off-by: Alexander Potapenko Acked-by: Michael S. Tsirkin --- Link: https://linux-review.googlesource.com/id/I211533ecb86a66624e151551f83= ddd749536b3af --- drivers/virtio/virtio_ring.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 962f1477b1fab..461e08f7f0a0f 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include =20 @@ -331,8 +332,15 @@ static dma_addr_t vring_map_one_sg(const struct vring_= virtqueue *vq, struct scatterlist *sg, enum dma_data_direction direction) { - if (!vq->use_dma_api) + if (!vq->use_dma_api) { + /* + * If DMA is not used, KMSAN doesn't know that the scatterlist + * is initialized by the hardware. Explicitly check/unpoison it + * depending on the direction. + */ + kmsan_handle_dma(sg_page(sg), sg->offset, sg->length, direction); return (dma_addr_t)sg_phys(sg); + } =20 /* * We can't use dma_map_sg, because we don't use scatterlists in --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6C9EC433F5 for ; Tue, 29 Mar 2022 12:43:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236592AbiC2Mpa (ORCPT ); Tue, 29 Mar 2022 08:45:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236653AbiC2Mn7 (ORCPT ); Tue, 29 Mar 2022 08:43:59 -0400 Received: from mail-wm1-x349.google.com (mail-wm1-x349.google.com [IPv6:2a00:1450:4864:20::349]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 56172220336 for ; Tue, 29 Mar 2022 05:41:43 -0700 (PDT) Received: by mail-wm1-x349.google.com with SMTP id t2-20020a7bc3c2000000b003528fe59cb9so1194947wmj.5 for ; Tue, 29 Mar 2022 05:41:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=fD7vTHTdDGWZj4L/ZpXEU7Cya0QLQJr2pYgffDh+E8w=; b=N5UUNqK7Dai6IC1Y08iiwp58OrTPktY0M/5uk3b7VTaXlaZiBP0iSzQIB5Iqcuot/B gEdH6p8/PLZmopCfTne4pFI4BmtruzrBSebrmitvqAQQE668M5KU4xRexTBPV9uC7ymZ +zOyylf/ah4aCgFKkajbof9fP8R1DcGP/XfHg7RJHfBw7th9QUxFB2hzyRO/1i8jAYJw 4EiSRL5zIyd2VX+QXlGoJXv/JlIO0ZiPYaFKrDKxaDNsgIzCjmznnE0eBKYCbEdPOLhZ W2SH91MCEC/gi2icPHSfjByyfpBxvyMEggdLnFEEIDpgnzzwJUdxKAXvo4DKQ2rPKqaU 4f6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=fD7vTHTdDGWZj4L/ZpXEU7Cya0QLQJr2pYgffDh+E8w=; b=I5auLbaBJIEo8Xy+8ZibHtCna3B1tKx5nOQmxovO4orJTQ0T/dk2ewihlgM9D5zZ0m kMtklJ6RagSVkzYH2D3hDfZ7uGqlhvjAkoKvbYBfPr38/H2pvy76zhcFg520xgM6GOTj 3iheVg+HUBGrgKR+xdJJ+irbteYI0NYWmGhLSUJQ1QaQkelt7FfLL/ABIbGBAcTE5Qc5 6t8GrlbXYtDJSzvLxsu2WFbxAiCtm/3duW8LWwFNaJoDItfI53lhA+2VtuzUpZUs2Yez IFBJ5uf10ym3fuT0CqfmQkGCHWbFXinqzj10s47fFTWxhhefcJdAyRlHdVSHjr0D3lhN XCNA== X-Gm-Message-State: AOAM5329XqNjSiQoMZ5wr7Vhqg7FeRedo2nR44IdLMUPd0ixWrH9o46Y VU3bemvEuwa5fHz98S7elRBr+AIKXEQ= X-Google-Smtp-Source: ABdhPJxIDBdkZcX7+d/MV/S8nH/sLZTjHyeXwqLiz2xe0oEWISYLlV51D9JqwEaJHLYksvw574hlzkx8kmA= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a5d:6b4c:0:b0:1e6:8ece:62e8 with SMTP id x12-20020a5d6b4c000000b001e68ece62e8mr30978626wrw.201.1648557701775; Tue, 29 Mar 2022 05:41:41 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:56 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-28-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 27/48] kmsan: handle memory sent to/from USB From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Depending on the value of is_out kmsan_handle_urb() KMSAN either marks the data copied to the kernel from a USB device as initialized, or checks the data sent to the device for being initialized. Signed-off-by: Alexander Potapenko --- v2: -- move kmsan_handle_urb() implementation to this patch Link: https://linux-review.googlesource.com/id/Ifa67fb72015d4de14c30e971556= f99fc8b2ee506 --- drivers/usb/core/urb.c | 2 ++ include/linux/kmsan.h | 15 +++++++++++++++ mm/kmsan/hooks.c | 17 +++++++++++++++++ 3 files changed, 34 insertions(+) diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c index 33d62d7e3929f..1fe3f23205624 100644 --- a/drivers/usb/core/urb.c +++ b/drivers/usb/core/urb.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -426,6 +427,7 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL | URB_DMA_SG_COMBINED); urb->transfer_flags |=3D (is_out ? URB_DIR_OUT : URB_DIR_IN); + kmsan_handle_urb(urb, is_out); =20 if (xfertype !=3D USB_ENDPOINT_XFER_CONTROL && dev->state < USB_STATE_CONFIGURED) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index d8667161a10c8..55f976b721566 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -20,6 +20,7 @@ struct page; struct kmem_cache; struct task_struct; struct scatterlist; +struct urb; =20 #ifdef CONFIG_KMSAN =20 @@ -236,6 +237,16 @@ void kmsan_handle_dma(struct page *page, size_t offset= , size_t size, void kmsan_handle_dma_sg(struct scatterlist *sg, int nents, enum dma_data_direction dir); =20 +/** + * kmsan_handle_urb() - Handle a USB data transfer. + * @urb: struct urb pointer. + * @is_out: data transfer direction (true means output to hardware). + * + * If @is_out is true, KMSAN checks the transfer buffer of @urb. Otherwise, + * KMSAN initializes the transfer buffer. + */ +void kmsan_handle_urb(const struct urb *urb, bool is_out); + #else =20 static inline void kmsan_init_shadow(void) @@ -328,6 +339,10 @@ static inline void kmsan_handle_dma_sg(struct scatterl= ist *sg, int nents, { } =20 +static inline void kmsan_handle_urb(const struct urb *urb, bool is_out) +{ +} + #endif =20 #endif /* _LINUX_KMSAN_H */ diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index cc3465bd69754..d95fd16a4b1dc 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -17,6 +17,7 @@ #include #include #include +#include =20 #include "../internal.h" #include "../slab.h" @@ -252,6 +253,22 @@ void kmsan_copy_to_user(void __user *to, const void *f= rom, size_t to_copy, } EXPORT_SYMBOL(kmsan_copy_to_user); =20 +/* Helper function to check an URB. */ +void kmsan_handle_urb(const struct urb *urb, bool is_out) +{ + if (!urb) + return; + if (is_out) + kmsan_internal_check_memory(urb->transfer_buffer, + urb->transfer_buffer_length, + /*user_addr*/ 0, REASON_SUBMIT_URB); + else + kmsan_internal_unpoison_memory(urb->transfer_buffer, + urb->transfer_buffer_length, + /*checked*/ false); +} +EXPORT_SYMBOL(kmsan_handle_urb); + static void kmsan_handle_dma_page(const void *addr, size_t size, enum dma_data_direction dir) { --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A92EFC433FE for ; Tue, 29 Mar 2022 12:44:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236445AbiC2Mpw (ORCPT ); Tue, 29 Mar 2022 08:45:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236597AbiC2MoF (ORCPT ); Tue, 29 Mar 2022 08:44:05 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22543236B9B for ; Tue, 29 Mar 2022 05:41:46 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id do20-20020a170906c11400b006e0de97a0e9so3083996ejc.19 for ; Tue, 29 Mar 2022 05:41:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=NcXyKO/GU5wv+AINtBvHToR0v2IpKVpreq+8SU9KtO4=; b=DIWfKg7bP7QnSfYaoX5/svSrQlbraANJFz4ZkJPOWATm87bCAU2GbOOvwevJcEHoKi wbdwLM4FSdQAgqD+aGltFF1nNlgaZOezyHxrai+rBf8lAExLt9TsIObDqEZCzGpIi7nH xwWzJXVyfWrhAFtE1DDgdB13tMX7M2TNnBpf5xo5AKOhlt6Ra/sgjz/MvMdpU1BtHlRO AokxmkFDUGancBTS6WUAyS0jZ1/25Z/5/NnX5iVI36FKkApjAbgSShp4qxN4eRySlGQN LaDPdH7+3zFsETzZOVpB1jP5H2P3l6+9CkkA76YAQaezI3vMYZPtpAZ47ee1hp/xomfj t6zg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=NcXyKO/GU5wv+AINtBvHToR0v2IpKVpreq+8SU9KtO4=; b=bMDzZNdiTXyTf29dFM8CRqBoAHU7IKe9szeT2d0RsQpk5TJtb5K+o4KKcnMW/7NspH Rbbq61fJoqhlQ/S61diPza/65AsU+FcEoSPZFocWRJ7dwZl58Mo9FG0tV3d2u2TfGlg8 EaobwBn4tE6LadKAmc09hY3vT2fX2CVTz6mk/SKHukTYdENtX9rKFvBF7RCB23EGoHUQ 2yuTyWn6dnzhEaxecCA5GakHumeFICqrlEgtX+BnIPZ0O+iLNGkSUtJaCuE57K5edDVn FMnj/XXITFYrJGIy/rR12dofFzv69msDvwrYSdXZraLFVTZAhehZA6YE7rZtdmlsRsXw JR8w== X-Gm-Message-State: AOAM530P0WqD0WabTaIHu5fpn59tVBTJ8I4QXGyHe8xqzzmY+5yX0lGQ NXz3Dy3WbPjFMYYG+RMdpWAvglcnKxM= X-Google-Smtp-Source: ABdhPJwPdBpHIJ0mASGI8QRZZRZI3D7LOk/yhFizlkS2OYABeZsKpvCixcNsVmSaozXNqIJyvElCXIKXLNA= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:1dc8:b0:6df:f5fc:f4f9 with SMTP id og8-20020a1709071dc800b006dff5fcf4f9mr34096038ejc.739.1648557704420; Tue, 29 Mar 2022 05:41:44 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:57 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-29-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 28/48] kmsan: instrumentation.h: add instrumentation_begin_with_regs() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When calling KMSAN-instrumented functions from non-instrumented functions, function parameters may not be initialized properly, leading to false positive reports. In particular, this happens all the time when calling interrupt handlers from `noinstr` IDT entries. We introduce instrumentation_begin_with_regs(), which calls instrumentation_begin() and notifies KMSAN about the beginning of the potentially instrumented region by calling kmsan_instrumentation_begin(), which: - wipes the current KMSAN state at the beginning of the region, ensuring that the first call of an instrumented function receives initialized parameters (this is a pretty good approximation of having all other instrumented functions receive initialized parameters); - unpoisons the `struct pt_regs` set up by the non-instrumented assembly code. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I0f5e3372e00bd5fe25ddbf286f7= 260aae9011858 --- include/linux/instrumentation.h | 6 ++++++ include/linux/kmsan.h | 11 +++++++++++ mm/kmsan/hooks.c | 16 ++++++++++++++++ 3 files changed, 33 insertions(+) diff --git a/include/linux/instrumentation.h b/include/linux/instrumentatio= n.h index 24359b4a96053..3bbce9d556381 100644 --- a/include/linux/instrumentation.h +++ b/include/linux/instrumentation.h @@ -15,6 +15,11 @@ }) #define instrumentation_begin() __instrumentation_begin(__COUNTER__) =20 +#define instrumentation_begin_with_regs(regs) do { \ + __instrumentation_begin(__COUNTER__); \ + kmsan_instrumentation_begin(regs); \ +} while (0) + /* * Because instrumentation_{begin,end}() can nest, objtool validation cons= iders * _begin() a +1 and _end() a -1 and computes a sum over the instructions. @@ -55,6 +60,7 @@ #define instrumentation_end() __instrumentation_end(__COUNTER__) #else # define instrumentation_begin() do { } while(0) +# define instrumentation_begin_with_regs(regs) kmsan_instrumentation_begin= (regs) # define instrumentation_end() do { } while(0) #endif =20 diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index 55f976b721566..209a5a2192e22 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -247,6 +247,13 @@ void kmsan_handle_dma_sg(struct scatterlist *sg, int n= ents, */ void kmsan_handle_urb(const struct urb *urb, bool is_out); =20 +/** + * kmsan_instrumentation_begin() - handle instrumentation_begin(). + * @regs: pointer to struct pt_regs that non-instrumented code passes to + * instrumented code. + */ +void kmsan_instrumentation_begin(struct pt_regs *regs); + #else =20 static inline void kmsan_init_shadow(void) @@ -343,6 +350,10 @@ static inline void kmsan_handle_urb(const struct urb *= urb, bool is_out) { } =20 +static inline void kmsan_instrumentation_begin(struct pt_regs *regs) +{ +} + #endif =20 #endif /* _LINUX_KMSAN_H */ diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index d95fd16a4b1dc..6b133533ff7d9 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -366,3 +366,19 @@ void kmsan_check_memory(const void *addr, size_t size) REASON_ANY); } EXPORT_SYMBOL(kmsan_check_memory); + +void kmsan_instrumentation_begin(struct pt_regs *regs) +{ + struct kmsan_context_state *state =3D &kmsan_get_context()->cstate; + + if (state) + __memset(state, 0, sizeof(struct kmsan_context_state)); + if (!kmsan_enabled || !regs) + return; + /* + * @regs may reside in cpu_entry_area, for which KMSAN does not allocate + * metadata. Do not force an error in that case. + */ + kmsan_internal_unpoison_memory(regs, sizeof(*regs), /*checked*/ false); +} +EXPORT_SYMBOL(kmsan_instrumentation_begin); --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC041C433EF for ; Tue, 29 Mar 2022 12:45:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236679AbiC2Mqk (ORCPT ); Tue, 29 Mar 2022 08:46:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34040 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236674AbiC2Moh (ORCPT ); Tue, 29 Mar 2022 08:44:37 -0400 Received: from mail-ej1-x64a.google.com (mail-ej1-x64a.google.com [IPv6:2a00:1450:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5028238D2B for ; Tue, 29 Mar 2022 05:41:48 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id my15-20020a1709065a4f00b006dfd2b16e6cso8136010ejc.1 for ; Tue, 29 Mar 2022 05:41:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=O02VuhTFNs3OTl+6EdHhE8hyAxR47CEkJ1c0ak5Vr4s=; b=C7gGD19m/XveB8Ws/Mrjzquo4UNw5iFhMF9IPlHcdW4Pk7ozQxZ0PNkEpCOMh/tb00 yCiWkUdHR91r9//CRvGweQPLnnFSzPbvrVzmonGkPHKHJKpSLL7cZLAlDCFYeFIGL0Ss /IHCNCWokewlL1qO8a1mb2PQPEKWlCRk5OzGhzGAqj2hGFDN9YdHtSVskka/fzfTrsMa j1HMSwQQR8sw9adaQ+zA9d1GRw1pKIsT10NfugO2m9bXeTnFmGN1T9OiXau82BOJCc7K C/JGIJ/LSEbzSTmqkiIN+J1LwkC97hJDp0NnsDzTO1d3X/gZnjcZCBRAdS59i777oAr4 GMUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=O02VuhTFNs3OTl+6EdHhE8hyAxR47CEkJ1c0ak5Vr4s=; b=rZVfnC+VxffSGzgk0JPbYpiyMyed5FmD2TIIUpINQWkkT5NCGrHqxhUKYPKTimkm/E y79THzfGbW3WobUD1qa03QnszKsKgdb/oziLfzp0JLDCEAHWPDVZY6az/78sc5d2DkYS WcJX4qvGyFPp0oPLwqAlERLtaFjYV/nAtLgOZe+fjdyY4BL6wsOP9JU/GMeDzEgUWiwj mN3n9QkJj2mLmgwMZZo8Flz8HkuvwirW/gJ2gX/BOkulgBmsTdJv5hYNK3NOFkGUgZrL K9okZeVCo8V4uRb4ZMXGc2gWsLpTMEYxA0p+eCBSiKgIyGBmGd6rPOz2GWS/Ew7tFFqD weEw== X-Gm-Message-State: AOAM530Yws6D2/rZmurJjS6zxb2TrDxBMYza/YhblOj1RgTjnir34L1D 9jByflcfbPPnPC0DinJH45MU8akoIyY= X-Google-Smtp-Source: ABdhPJyB/bcFcN+qpi65yKy1mIxhG89Sd6SxBmOpeaEdxDCuTuOOvV2uj+2kKbIDqHQp3uDGpI9M/qBVr2s= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:4786:b0:6e0:c7b:d267 with SMTP id cw6-20020a170906478600b006e00c7bd267mr34808708ejc.115.1648557707096; Tue, 29 Mar 2022 05:41:47 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:58 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-30-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 29/48] kmsan: entry: handle register passing from uninstrumented code From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Replace instrumentation_begin() with instrumentation_begin_with_regs() to let KMSAN handle the non-instrumented code and unpoison pt_regs passed from the instrumented part. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I7f0a9809b66bd85faae43142971= d0095771b7a42 --- kernel/entry/common.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/kernel/entry/common.c b/kernel/entry/common.c index bad713684c2e3..dcf91ab14512a 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -21,7 +21,7 @@ static __always_inline void __enter_from_user_mode(struct= pt_regs *regs) CT_WARN_ON(ct_state() !=3D CONTEXT_USER); user_exit_irqoff(); =20 - instrumentation_begin(); + instrumentation_begin_with_regs(regs); trace_hardirqs_off_finish(); instrumentation_end(); } @@ -103,7 +103,7 @@ noinstr long syscall_enter_from_user_mode(struct pt_reg= s *regs, long syscall) =20 __enter_from_user_mode(regs); =20 - instrumentation_begin(); + instrumentation_begin_with_regs(regs); local_irq_enable(); ret =3D __syscall_enter_from_user_work(regs, syscall); instrumentation_end(); @@ -114,7 +114,7 @@ noinstr long syscall_enter_from_user_mode(struct pt_reg= s *regs, long syscall) noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs) { __enter_from_user_mode(regs); - instrumentation_begin(); + instrumentation_begin_with_regs(regs); local_irq_enable(); instrumentation_end(); } @@ -296,7 +296,7 @@ void syscall_exit_to_user_mode_work(struct pt_regs *reg= s) =20 __visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs) { - instrumentation_begin(); + instrumentation_begin_with_regs(regs); __syscall_exit_to_user_mode_work(regs); instrumentation_end(); __exit_to_user_mode(); @@ -309,7 +309,7 @@ noinstr void irqentry_enter_from_user_mode(struct pt_re= gs *regs) =20 noinstr void irqentry_exit_to_user_mode(struct pt_regs *regs) { - instrumentation_begin(); + instrumentation_begin_with_regs(regs); exit_to_user_mode_prepare(regs); instrumentation_end(); __exit_to_user_mode(); @@ -357,7 +357,7 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs = *regs) */ lockdep_hardirqs_off(CALLER_ADDR0); rcu_irq_enter(); - instrumentation_begin(); + instrumentation_begin_with_regs(regs); trace_hardirqs_off_finish(); instrumentation_end(); =20 @@ -372,7 +372,7 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs = *regs) * in having another one here. */ lockdep_hardirqs_off(CALLER_ADDR0); - instrumentation_begin(); + instrumentation_begin_with_regs(regs); rcu_irq_enter_check_tick(); trace_hardirqs_off_finish(); instrumentation_end(); @@ -409,7 +409,7 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqent= ry_state_t state) * and RCU as the return to user mode path. */ if (state.exit_rcu) { - instrumentation_begin(); + instrumentation_begin_with_regs(regs); /* Tell the tracer that IRET will enable interrupts */ trace_hardirqs_on_prepare(); lockdep_hardirqs_on_prepare(CALLER_ADDR0); @@ -419,7 +419,7 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqent= ry_state_t state) return; } =20 - instrumentation_begin(); + instrumentation_begin_with_regs(regs); if (IS_ENABLED(CONFIG_PREEMPTION)) { #ifdef CONFIG_PREEMPT_DYNAMIC static_call(irqentry_exit_cond_resched)(); @@ -451,7 +451,7 @@ irqentry_state_t noinstr irqentry_nmi_enter(struct pt_r= egs *regs) lockdep_hardirq_enter(); rcu_nmi_enter(); =20 - instrumentation_begin(); + instrumentation_begin_with_regs(regs); trace_hardirqs_off_finish(); ftrace_nmi_enter(); instrumentation_end(); @@ -461,7 +461,7 @@ irqentry_state_t noinstr irqentry_nmi_enter(struct pt_r= egs *regs) =20 void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_= state) { - instrumentation_begin(); + instrumentation_begin_with_regs(regs); ftrace_nmi_exit(); if (irq_state.lockdep) { trace_hardirqs_on_prepare(); --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 319C9C433EF for ; Tue, 29 Mar 2022 12:45:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236005AbiC2Mq4 (ORCPT ); Tue, 29 Mar 2022 08:46:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236710AbiC2Mop (ORCPT ); Tue, 29 Mar 2022 08:44:45 -0400 Received: from mail-ej1-x64a.google.com (mail-ej1-x64a.google.com [IPv6:2a00:1450:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8D1023B3CB for ; Tue, 29 Mar 2022 05:41:51 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id hg13-20020a1709072ccd00b006dfa484ec23so8156577ejc.8 for ; Tue, 29 Mar 2022 05:41:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=ORrNB40QDu3vcG+RZ93rBZX+e6sP+7+NX9TJISDi1qU=; b=oUfuMQe4TQ+YUVO04o+/5f035up8s48zJgn2wOB/vGVKcysfaPQ3rpHsQsQnxAlk2K O+mWJ0G9+ApPZSexcv6yXSJQoAKL86AfFqHN+FQxYZUtsm9vcZJt2gzIoYs97OoNBD50 umhg213hsSqiC935IB+uL6VLQdbGU3Ddo76zvvBGgNg1Kmv2tT1jmJwsyuxQpZ0C1lko HLeRJP/YxjgQf957b46rdio72dqlF51FUpXKUhih35es6QcqUbPB070b8fwciMoDAzGl 0edohXBEVCzP8AUEcgY81RWhPpdiDspDAI83AE5JKZFXGiFj/H15DHThcw7C+hs7HWLk /EkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ORrNB40QDu3vcG+RZ93rBZX+e6sP+7+NX9TJISDi1qU=; b=a+5eMhSuKTqZgT/N8tG6ZAYVN59YyRdL+M28H1n0kvL8ePfGfXPMOK5d7S9fwNcHMh attE/eOiFX42ec/gg6/oFgW2Iz/K6yiHi/e+HjUGcsh081iydYQNJL3PIqJFgD3Gs3oW xlLSmv8GpYsoSOqHbKeqA2YKA1EKYLIu7uyJhbhyNj9m79RI/gdEcZmWCBKo+MYiwt+x 2g27gP88JBUHmoQArxuJrY51JPFe1lP8+Cz3QyOuDGN2pNwJr7dUyMVaVB8My+dOcWZj oPZ4hPUTsQfPW5TIrb3qMxXyNxwWQ1dh5RLQaQtvICjyJxjRXyT3AuQPeXwOXP+aRy/0 LXrg== X-Gm-Message-State: AOAM530XAghVZIrhb5cTTWLCPz2UWYXcRVSmOWbKBcr3UgcO7rklZodH bmyaSuBySQMtpvj05cgi8uCdxaqorik= X-Google-Smtp-Source: ABdhPJwKLhapJB5OnJLqm/L8rpOj5PpjmP7ckM5yXynxdh1052FVxkjBNwGwfBfb35psEULLalcUgLvNcDs= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a05:6402:5186:b0:419:49af:428f with SMTP id q6-20020a056402518600b0041949af428fmr4323040edd.177.1648557709877; Tue, 29 Mar 2022 05:41:49 -0700 (PDT) Date: Tue, 29 Mar 2022 14:39:59 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-31-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 30/48] kmsan: add tests for KMSAN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The testing module triggers KMSAN warnings in different cases and checks that the errors are properly reported, using console probes to capture the tool's output. Signed-off-by: Alexander Potapenko --- v2: -- add memcpy tests Link: https://linux-review.googlesource.com/id/I49c3f59014cc37fd13541c80beb= 0b75a75244650 --- lib/Kconfig.kmsan | 16 ++ mm/kmsan/Makefile | 4 + mm/kmsan/kmsan_test.c | 536 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 556 insertions(+) create mode 100644 mm/kmsan/kmsan_test.c diff --git a/lib/Kconfig.kmsan b/lib/Kconfig.kmsan index 199f79d031f94..a68fdb5ed5d92 100644 --- a/lib/Kconfig.kmsan +++ b/lib/Kconfig.kmsan @@ -21,3 +21,19 @@ config KMSAN the whole system down. =20 See for more details. + +if KMSAN + +config KMSAN_KUNIT_TEST + tristate "KMSAN integration test suite" if !KUNIT_ALL_TESTS + default KUNIT_ALL_TESTS + depends on TRACEPOINTS && KUNIT + help + Test suite for KMSAN, testing various error detection scenarios, + and checking that reports are correctly output to console. + + Say Y here if you want the test to be built into the kernel and run + during boot; say M if you want the test to build as a module; say N + if you are unsure. + +endif diff --git a/mm/kmsan/Makefile b/mm/kmsan/Makefile index f57a956cb1c8b..7be6a7e92394f 100644 --- a/mm/kmsan/Makefile +++ b/mm/kmsan/Makefile @@ -20,3 +20,7 @@ CFLAGS_init.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_instrumentation.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_report.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_shadow.o :=3D $(CC_FLAGS_KMSAN_RUNTIME) + +obj-$(CONFIG_KMSAN_KUNIT_TEST) +=3D kmsan_test.o +KMSAN_SANITIZE_kmsan_test.o :=3D y +CFLAGS_kmsan_test.o +=3D $(call cc-disable-warning, uninitialized) diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c new file mode 100644 index 0000000000000..44bb2e0f87d81 --- /dev/null +++ b/mm/kmsan/kmsan_test.c @@ -0,0 +1,536 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test cases for KMSAN. + * For each test case checks the presence (or absence) of generated report= s. + * Relies on 'console' tracepoint to capture reports as they appear in the + * kernel log. + * + * Copyright (C) 2021-2022, Google LLC. + * Author: Alexander Potapenko + * + */ + +#include +#include "kmsan.h" + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_PER_CPU(int, per_cpu_var); + +/* Report as observed from console. */ +static struct { + spinlock_t lock; + bool available; + bool ignore; /* Stop console output collection. */ + char header[256]; +} observed =3D { + .lock =3D __SPIN_LOCK_UNLOCKED(observed.lock), +}; + +/* Probe for console output: obtains observed lines of interest. */ +static void probe_console(void *ignore, const char *buf, size_t len) +{ + unsigned long flags; + + if (observed.ignore) + return; + spin_lock_irqsave(&observed.lock, flags); + + if (strnstr(buf, "BUG: KMSAN: ", len)) { + /* + * KMSAN report and related to the test. + * + * The provided @buf is not NUL-terminated; copy no more than + * @len bytes and let strscpy() add the missing NUL-terminator. + */ + strscpy(observed.header, buf, + min(len + 1, sizeof(observed.header))); + WRITE_ONCE(observed.available, true); + observed.ignore =3D true; + } + spin_unlock_irqrestore(&observed.lock, flags); +} + +/* Check if a report related to the test exists. */ +static bool report_available(void) +{ + return READ_ONCE(observed.available); +} + +/* Information we expect in a report. */ +struct expect_report { + const char *error_type; /* Error type. */ + /* + * Kernel symbol from the error header, or NULL if no report is + * expected. + */ + const char *symbol; +}; + +/* Check observed report matches information in @r. */ +static bool report_matches(const struct expect_report *r) +{ + typeof(observed.header) expected_header; + unsigned long flags; + bool ret =3D false; + const char *end; + char *cur; + + /* Doubled-checked locking. */ + if (!report_available() || !r->symbol) + return (!report_available() && !r->symbol); + + /* Generate expected report contents. */ + + /* Title */ + cur =3D expected_header; + end =3D &expected_header[sizeof(expected_header) - 1]; + + cur +=3D scnprintf(cur, end - cur, "BUG: KMSAN: %s", r->error_type); + + scnprintf(cur, end - cur, " in %s", r->symbol); + /* The exact offset won't match, remove it; also strip module name. */ + cur =3D strchr(expected_header, '+'); + if (cur) + *cur =3D '\0'; + + spin_lock_irqsave(&observed.lock, flags); + if (!report_available()) + goto out; /* A new report is being captured. */ + + /* Finally match expected output to what we actually observed. */ + ret =3D strstr(observed.header, expected_header); +out: + spin_unlock_irqrestore(&observed.lock, flags); + + return ret; +} + +/* =3D=3D=3D=3D=3D Test cases =3D=3D=3D=3D=3D */ + +/* Prevent replacing branch with select in LLVM. */ +static noinline void check_true(char *arg) +{ + pr_info("%s is true\n", arg); +} + +static noinline void check_false(char *arg) +{ + pr_info("%s is false\n", arg); +} + +#define USE(x) = \ + do { \ + if (x) \ + check_true(#x); \ + else \ + check_false(#x); \ + } while (0) + +#define EXPECTATION_ETYPE_FN(e, reason, fn) = \ + struct expect_report e =3D { \ + .error_type =3D reason, \ + .symbol =3D fn, \ + } + +#define EXPECTATION_NO_REPORT(e) EXPECTATION_ETYPE_FN(e, NULL, NULL) +#define EXPECTATION_UNINIT_VALUE_FN(e, fn) = \ + EXPECTATION_ETYPE_FN(e, "uninit-value", fn) +#define EXPECTATION_UNINIT_VALUE(e) EXPECTATION_UNINIT_VALUE_FN(e, __func_= _) +#define EXPECTATION_USE_AFTER_FREE(e) = \ + EXPECTATION_ETYPE_FN(e, "use-after-free", __func__) + +/* Test case: ensure that kmalloc() returns uninitialized memory. */ +static void test_uninit_kmalloc(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE(expect); + int *ptr; + + kunit_info(test, "uninitialized kmalloc test (UMR report)\n"); + ptr =3D kmalloc(sizeof(int), GFP_KERNEL); + USE(*ptr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* + * Test case: ensure that kmalloc'ed memory becomes initialized after mems= et(). + */ +static void test_init_kmalloc(struct kunit *test) +{ + EXPECTATION_NO_REPORT(expect); + int *ptr; + + kunit_info(test, "initialized kmalloc test (no reports)\n"); + ptr =3D kmalloc(sizeof(int), GFP_KERNEL); + memset(ptr, 0, sizeof(int)); + USE(*ptr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* Test case: ensure that kzalloc() returns initialized memory. */ +static void test_init_kzalloc(struct kunit *test) +{ + EXPECTATION_NO_REPORT(expect); + int *ptr; + + kunit_info(test, "initialized kzalloc test (no reports)\n"); + ptr =3D kzalloc(sizeof(int), GFP_KERNEL); + USE(*ptr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* Test case: ensure that local variables are uninitialized by default. */ +static void test_uninit_stack_var(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE(expect); + volatile int cond; + + kunit_info(test, "uninitialized stack variable (UMR report)\n"); + USE(cond); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* Test case: ensure that local variables with initializers are initialize= d. */ +static void test_init_stack_var(struct kunit *test) +{ + EXPECTATION_NO_REPORT(expect); + volatile int cond =3D 1; + + kunit_info(test, "initialized stack variable (no reports)\n"); + USE(cond); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static noinline void two_param_fn_2(int arg1, int arg2) +{ + USE(arg1); + USE(arg2); +} + +static noinline void one_param_fn(int arg) +{ + two_param_fn_2(arg, arg); + USE(arg); +} + +static noinline void two_param_fn(int arg1, int arg2) +{ + int init =3D 0; + + one_param_fn(init); + USE(arg1); + USE(arg2); +} + +static void test_params(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE_FN(expect, "two_param_fn"); + volatile int uninit, init =3D 1; + + kunit_info(test, + "uninit passed through a function parameter (UMR report)\n"); + two_param_fn(uninit, init); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static int signed_sum3(int a, int b, int c) +{ + return a + b + c; +} + +/* + * Test case: ensure that uninitialized values are tracked through function + * arguments. + */ +static void test_uninit_multiple_params(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE(expect); + volatile char b =3D 3, c; + volatile int a; + + kunit_info(test, "uninitialized local passed to fn (UMR report)\n"); + USE(signed_sum3(a, b, c)); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* Helper function to make an array uninitialized. */ +static noinline void do_uninit_local_array(char *array, int start, int sto= p) +{ + volatile char uninit; + int i; + + for (i =3D start; i < stop; i++) + array[i] =3D uninit; +} + +/* + * Test case: ensure kmsan_check_memory() reports an error when checking + * uninitialized memory. + */ +static void test_uninit_kmsan_check_memory(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE_FN(expect, "test_uninit_kmsan_check_memory"); + volatile char local_array[8]; + + kunit_info( + test, + "kmsan_check_memory() called on uninit local (UMR report)\n"); + do_uninit_local_array((char *)local_array, 5, 7); + + kmsan_check_memory((char *)local_array, 8); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* + * Test case: check that a virtual memory range created with vmap() from + * initialized pages is still considered as initialized. + */ +static void test_init_kmsan_vmap_vunmap(struct kunit *test) +{ + EXPECTATION_NO_REPORT(expect); + const int npages =3D 2; + struct page **pages; + void *vbuf; + int i; + + kunit_info(test, "pages initialized via vmap (no reports)\n"); + + pages =3D kmalloc_array(npages, sizeof(struct page), GFP_KERNEL); + for (i =3D 0; i < npages; i++) + pages[i] =3D alloc_page(GFP_KERNEL); + vbuf =3D vmap(pages, npages, VM_MAP, PAGE_KERNEL); + memset(vbuf, 0xfe, npages * PAGE_SIZE); + for (i =3D 0; i < npages; i++) + kmsan_check_memory(page_address(pages[i]), PAGE_SIZE); + + if (vbuf) + vunmap(vbuf); + for (i =3D 0; i < npages; i++) + if (pages[i]) + __free_page(pages[i]); + kfree(pages); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* + * Test case: ensure that memset() can initialize a buffer allocated via + * vmalloc(). + */ +static void test_init_vmalloc(struct kunit *test) +{ + EXPECTATION_NO_REPORT(expect); + int npages =3D 8, i; + char *buf; + + kunit_info(test, "vmalloc buffer can be initialized (no reports)\n"); + buf =3D vmalloc(PAGE_SIZE * npages); + buf[0] =3D 1; + memset(buf, 0xfe, PAGE_SIZE * npages); + USE(buf[0]); + for (i =3D 0; i < npages; i++) + kmsan_check_memory(&buf[PAGE_SIZE * i], PAGE_SIZE); + vfree(buf); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* Test case: ensure that use-after-free reporting works. */ +static void test_uaf(struct kunit *test) +{ + EXPECTATION_USE_AFTER_FREE(expect); + volatile int value; + volatile int *var; + + kunit_info(test, "use-after-free in kmalloc-ed buffer (UMR report)\n"); + var =3D kmalloc(80, GFP_KERNEL); + var[3] =3D 0xfeedface; + kfree((int *)var); + /* Copy the invalid value before checking it. */ + value =3D var[3]; + USE(value); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* + * Test case: ensure that uninitialized values are propagated through per-= CPU + * memory. + */ +static void test_percpu_propagate(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE(expect); + volatile int uninit, check; + + kunit_info(test, + "uninit local stored to per_cpu memory (UMR report)\n"); + + this_cpu_write(per_cpu_var, uninit); + check =3D this_cpu_read(per_cpu_var); + USE(check); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* + * Test case: ensure that passing uninitialized values to printk() leads t= o an + * error report. + */ +static void test_printk(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE_FN(expect, "number"); + volatile int uninit; + + kunit_info(test, "uninit local passed to pr_info() (UMR report)\n"); + pr_info("%px contains %d\n", &uninit, uninit); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* + * Test case: ensure that memcpy() correctly copies uninitialized values b= etween + * aligned `src` and `dst`. + */ +static void test_memcpy_aligned_to_aligned(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE_FN(expect, "test_memcpy_aligned_to_aligned"); + volatile int uninit_src; + volatile int dst =3D 0; + + kunit_info(test, "memcpy()ing aligned uninit src to aligned dst (UMR repo= rt)\n"); + memcpy((void *)&dst, (void *)&uninit_src, sizeof(uninit_src)); + kmsan_check_memory((void *)&dst, sizeof(dst)); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* + * Test case: ensure that memcpy() correctly copies uninitialized values b= etween + * aligned `src` and unaligned `dst`. + * + * Copying aligned 4-byte value to an unaligned one leads to touching two + * aligned 4-byte values. This test case checks that KMSAN correctly repor= ts an + * error on the first of the two values. + */ +static void test_memcpy_aligned_to_unaligned(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE_FN(expect, "test_memcpy_aligned_to_unaligned"); + volatile int uninit_src; + volatile char dst[8] =3D {0}; + + kunit_info(test, "memcpy()ing aligned uninit src to unaligned dst (UMR re= port)\n"); + memcpy((void *)&dst[1], (void *)&uninit_src, sizeof(uninit_src)); + kmsan_check_memory((void *)dst, 4); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* + * Test case: ensure that memcpy() correctly copies uninitialized values b= etween + * aligned `src` and unaligned `dst`. + * + * Copying aligned 4-byte value to an unaligned one leads to touching two + * aligned 4-byte values. This test case checks that KMSAN correctly repor= ts an + * error on the second of the two values. + */ +static void test_memcpy_aligned_to_unaligned2(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE_FN(expect, "test_memcpy_aligned_to_unaligned2"); + volatile int uninit_src; + volatile char dst[8] =3D {0}; + + kunit_info(test, "memcpy()ing aligned uninit src to unaligned dst - part = 2 (UMR report)\n"); + memcpy((void *)&dst[1], (void *)&uninit_src, sizeof(uninit_src)); + kmsan_check_memory((void *)&dst[4], sizeof(uninit_src)); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static struct kunit_case kmsan_test_cases[] =3D { + KUNIT_CASE(test_uninit_kmalloc), + KUNIT_CASE(test_init_kmalloc), + KUNIT_CASE(test_init_kzalloc), + KUNIT_CASE(test_uninit_stack_var), + KUNIT_CASE(test_init_stack_var), + KUNIT_CASE(test_params), + KUNIT_CASE(test_uninit_multiple_params), + KUNIT_CASE(test_uninit_kmsan_check_memory), + KUNIT_CASE(test_init_kmsan_vmap_vunmap), + KUNIT_CASE(test_init_vmalloc), + KUNIT_CASE(test_uaf), + KUNIT_CASE(test_percpu_propagate), + KUNIT_CASE(test_printk), + KUNIT_CASE(test_memcpy_aligned_to_aligned), + KUNIT_CASE(test_memcpy_aligned_to_unaligned), + KUNIT_CASE(test_memcpy_aligned_to_unaligned2), + {}, +}; + +/* =3D=3D=3D=3D=3D End test cases =3D=3D=3D=3D=3D */ + +static int test_init(struct kunit *test) +{ + unsigned long flags; + + spin_lock_irqsave(&observed.lock, flags); + observed.header[0] =3D '\0'; + observed.ignore =3D false; + observed.available =3D false; + spin_unlock_irqrestore(&observed.lock, flags); + + return 0; +} + +static void test_exit(struct kunit *test) +{ +} + +static struct kunit_suite kmsan_test_suite =3D { + .name =3D "kmsan", + .test_cases =3D kmsan_test_cases, + .init =3D test_init, + .exit =3D test_exit, +}; +static struct kunit_suite *kmsan_test_suites[] =3D { &kmsan_test_suite, NU= LL }; + +static void register_tracepoints(struct tracepoint *tp, void *ignore) +{ + check_trace_callback_type_console(probe_console); + if (!strcmp(tp->name, "console")) + WARN_ON(tracepoint_probe_register(tp, probe_console, NULL)); +} + +static void unregister_tracepoints(struct tracepoint *tp, void *ignore) +{ + if (!strcmp(tp->name, "console")) + tracepoint_probe_unregister(tp, probe_console, NULL); +} + +/* + * We only want to do tracepoints setup and teardown once, therefore we ha= ve to + * customize the init and exit functions and cannot rely on kunit_test_sui= te(). + */ +static int __init kmsan_test_init(void) +{ + /* + * Because we want to be able to build the test as a module, we need to + * iterate through all known tracepoints, since the static registration + * won't work here. + */ + for_each_kernel_tracepoint(register_tracepoints, NULL); + return __kunit_test_suites_init(kmsan_test_suites); +} + +static void kmsan_test_exit(void) +{ + __kunit_test_suites_exit(kmsan_test_suites); + for_each_kernel_tracepoint(unregister_tracepoints, NULL); + tracepoint_synchronize_unregister(); +} + +late_initcall_sync(kmsan_test_init); +module_exit(kmsan_test_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Alexander Potapenko "); --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1AB24C433FE for ; Tue, 29 Mar 2022 12:45:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234738AbiC2MrG (ORCPT ); Tue, 29 Mar 2022 08:47:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236652AbiC2MpX (ORCPT ); Tue, 29 Mar 2022 08:45:23 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A1E5523D745 for ; Tue, 29 Mar 2022 05:41:54 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id x1-20020a50f181000000b00418f6d4bccbso10995254edl.12 for ; Tue, 29 Mar 2022 05:41:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=enpw47tW5AlKxiO7mK8zQaDRtxatFy2+pOtakd8BlZk=; b=mCwjmjg5IEjrVFruDI8qNciYEOnA2jiLkX9pLqN6BnRcekJoE0XFuHwS9ksz9BZuKY n2Vq+3ICaYrPhLsEY2JcrP3sAWEO8412GRb/cLfojFWc/Jv/zfHf6VmhfoHQDyibrhRx 8IC9UaRnp3e1xpCjw97idSW8aarWoqZh0n2KfPjUQhED20Y5dJyYXlGP9d7TDcAtLJjJ tGVXH5XRlRg71IARaSa3IaKomYbSYugJMCjnDyryrStOIVf7B/EHB5TBnzADPTie1FVi apknmdO2z63KmAh6CYf0AHjMa0AeJ4eU4IOL9/Ql/UgZ21OFy1M4gXnTW1xPdquE8NbE svEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=enpw47tW5AlKxiO7mK8zQaDRtxatFy2+pOtakd8BlZk=; b=4SAhvzEAH360HXYhUMXwSsXzuhHI23fCoLVr3o6WbWZ1Iknv5sEo19qdFbArj/3Sgl RR4XwnbXHyBOPBATMmNtGrXDJFqv5uR65mQ/6UES7Wj02I/vnfWCbEsYDL10Wb5L3dVN 4k01fDFHCPxV9iTwGvQ2wMei5wnrtg6Q+ocgFpVeCU1xGnkqEwQYXUv2qXPecOZnIDUJ ymbSzI6dQvHobagiq8veyafTn0148wcKnNW2IzEOORCtJaR18U1DLrxM2GxRNW/YfZSB Cm3s7mUCOXXFQrcJsVZPjLX/r881Rnldunx7wOA/8/AI7jr43tubMiDd90R/UP9krEUp jR0g== X-Gm-Message-State: AOAM530fg57KOKKNdC32oqVYAKflsBzAK8mhV9xwNe8B07hwEbjswDYl sD9DWZXex8Willhe2Gc9+or2QdcL614= X-Google-Smtp-Source: ABdhPJyvopsmMnmkArFS+YVZS01vYvUWgOoKNLhFelQAgUTgMKFm4yxx2n/LM5t8wnbOjIRaXG8/wiLoWwo= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:6297:b0:6da:6388:dc58 with SMTP id nd23-20020a170907629700b006da6388dc58mr35414945ejc.472.1648557712510; Tue, 29 Mar 2022 05:41:52 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:00 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-32-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 31/48] kernel: kmsan: don't instrument stacktrace.c From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When unwinding stack traces, the kernel may pick uninitialized data from the stack. To avoid false reports on that data, we do not instrument stacktrace.c Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Iadb72036ff6868b1d7c9f1ed663= 0a66be6c57a42 --- kernel/Makefile | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/Makefile b/kernel/Makefile index 80f6cfb60c020..1147f0bd6e022 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -40,6 +40,11 @@ KASAN_SANITIZE_kcov.o :=3D n KCSAN_SANITIZE_kcov.o :=3D n UBSAN_SANITIZE_kcov.o :=3D n KMSAN_SANITIZE_kcov.o :=3D n + +# Code in stactrace.c may branch on random values taken from the stack. +# Prevent KMSAN false positives by not instrumenting this file. +KMSAN_SANITIZE_stacktrace.o :=3D n + CFLAGS_kcov.o :=3D $(call cc-option, -fno-conserve-stack) -fno-stack-prote= ctor =20 # Don't instrument error handlers --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B49BC433F5 for ; Tue, 29 Mar 2022 12:45:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236281AbiC2MrK (ORCPT ); Tue, 29 Mar 2022 08:47:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34868 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236597AbiC2MqG (ORCPT ); Tue, 29 Mar 2022 08:46:06 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23C0523F380 for ; Tue, 29 Mar 2022 05:41:57 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id z22-20020a50cd16000000b0041960ea8555so10962192edi.2 for ; Tue, 29 Mar 2022 05:41:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=RDAmLqPngdYXKHnjNo9GDMAFOLr0Hdlw9RyMH9Gzg2s=; b=FNcO9gUSy3+PyH4e35W5RF6+lKn5SBE99oNAhVPz9pbYEq9m/C8L6ZgtW5ZmHXHd88 hQHJyPhLbOckmp0EqPMhP2HFzsxaGQxiGxliYPsshxLsXZvRvNDQ3UiI+w2rcId/Pty2 F64ZcwqpBt31uCBn0TdlaFTImU9JlBg1RYV2VHIqSgThEHMQahV/qTUZD+t5uPqd7ue6 fH/tn196F1PiJHLimD7A+gQDUww4aLBtiNt+XEamDrdfD269XRiydzui+vDM+yTJPgEp rF70JXIzeqHaym/T57YbYOQSbgbJ7VSdFIY7t07gue+zb/IWNfau8QfmJWCRW+7p6THF iMvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=RDAmLqPngdYXKHnjNo9GDMAFOLr0Hdlw9RyMH9Gzg2s=; b=45hL1HBRzSO4jTPIfUpboyXSinmYPTy9cvT5vvzFRRTBlapSaQSTCBNu/swzExvbLs 2LpyP6MwApAmAbkItH6LsrqxF9vxvQAQkMx2/BrxGwpJEAXRqdXEjJ9gimG13NPr6bRm CwJWAfyTii7+kOWNa2VeOgmXNmnq5BxTk+R3EZbBteMp2Bi3WRkdkg9MM7Rs8XjzY4qu 4Wn7xvI0komk/B3OFQk1fFQQyp8XqIupG2ARs9YHyN5+HetyUTz10wCbYXfGgjF6vmP2 jnvr5E55OM6PCz1sstcx0G09j96Xk0zIV0Tsz3PrCozkcsUNETpMm1xtoS+jKvLsIuG7 qDFA== X-Gm-Message-State: AOAM531G9myZW01RhtvPZ8kzgRMZ3xPzChtTpP4b56cAZ6y5Naxzaec4 yjmGgXFLMBtyY2st3gQsmLB2L6smOPw= X-Google-Smtp-Source: ABdhPJzvRP1sTqhryqj6ueAWd65Bk5TF0Xd1dq7WPSkbBowXyk0DvSiadnoCaN6qak+2HIZ7cYi2Zk2fLDo= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:af6b:b0:6df:83a9:67db with SMTP id os11-20020a170906af6b00b006df83a967dbmr34685899ejb.222.1648557715258; Tue, 29 Mar 2022 05:41:55 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:01 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-33-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 32/48] kmsan: disable strscpy() optimization under KMSAN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Disable the efficient 8-byte reading under KMSAN to avoid false positives. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Iffd8336965e88fce915db2e6a9d= 6524422975f69 --- lib/string.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/lib/string.c b/lib/string.c index 485777c9da832..4ece4c7e7831b 100644 --- a/lib/string.c +++ b/lib/string.c @@ -197,6 +197,14 @@ ssize_t strscpy(char *dest, const char *src, size_t co= unt) max =3D 0; #endif =20 + /* + * read_word_at_a_time() below may read uninitialized bytes after the + * trailing zero and use them in comparisons. Disable this optimization + * under KMSAN to prevent false positive reports. + */ + if (IS_ENABLED(CONFIG_KMSAN)) + max =3D 0; + while (max >=3D sizeof(unsigned long)) { unsigned long c, data; =20 --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57B76C433F5 for ; Tue, 29 Mar 2022 12:45:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236693AbiC2Mr2 (ORCPT ); Tue, 29 Mar 2022 08:47:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34052 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236735AbiC2Mqq (ORCPT ); Tue, 29 Mar 2022 08:46:46 -0400 Received: from mail-ed1-x54a.google.com (mail-ed1-x54a.google.com [IPv6:2a00:1450:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C6282493D0 for ; Tue, 29 Mar 2022 05:42:00 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id u13-20020a50a40d000000b00419028f7f96so10941179edb.21 for ; Tue, 29 Mar 2022 05:42:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=C2KQWOZCabgVYfvOHTlGiLbP5VJcDGz40QZF+vn2Rc0=; b=QTYt9ALOL2uekj5EhavmcqsWsXm1i9tTG8lVqsixbMUAwldjnzPa1iDzQOX0A70yz8 rZ2AFCEZilfJ0aeA6qTNHyg3VcyIHeTwWo7kOmqAXeGPwO3fWdVa0C8Xa6VXQAlD4+Y6 4we8BlhM172eyBuCv/H43tzwj5DooXSoeJ1OQOT6wty0KgfRUGrTKTMg7sjoOZbr+GZQ h162PLcOdfLvVAUtf7cw9VNk8uejOkBnNekjdkyuuQjepaVKYqpAZA9/UhqLrHLGAIKG W46UQq3sCAo4Wono9Zi4fmnwXyNRv6konSpuKDMIK9u0VMX0KqUi5loVTdk36IKS+vKO HExQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=C2KQWOZCabgVYfvOHTlGiLbP5VJcDGz40QZF+vn2Rc0=; b=qKbSRFDciBrYHwh9l57qKz3MFktnYV/hNTbMZy2hHPQizOqmVL05bWY1FcaUm7sfYb O4X3OZD08gqAiaMD75W5bNMRXkd0A5Y0AAu3tgQfObR4YkTy0y3W9AD+9AuQ/u73KQI5 GGljItTF9rkDBdaYWuEuoZgJ4C2gopbTEHxb3KMI8FBzn0Id+RaaRTCyXIaUVq03ap5v h4TXe+xxQjRaXKltT0Av+K/rrh+p23uiWaINnp1RiBU2AkFMWKhdp2y+vfJQSbYOSVRb paieWxWaopIVy4w74im4wX04YpHrPnVKxBR60OqtrT/1NICfKMQn/ylR7j4I4gGxJjyH M/Nw== X-Gm-Message-State: AOAM5300vvut/d1/LPnnG5e0HQUNmJKmVz1JgNafcJ100L7eSjDeeRqo BZ3OBDxGQXr7zRuGECMx31OEWVtvpTU= X-Google-Smtp-Source: ABdhPJzqBcloD2KBNwEOa+2Cq88rT9VWS0jiDv0M/QAzLmjAZQp9Ior/Bcdzgfid36cN5BimbzeHjNpxRI0= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:2513:b0:6e1:2c10:2ada with SMTP id y19-20020a170907251300b006e12c102adamr5699618ejl.211.1648557717959; Tue, 29 Mar 2022 05:41:57 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:02 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-34-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 33/48] crypto: kmsan: disable accelerated configs under KMSAN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KMSAN is unable to understand when initialized values come from assembly. Disable accelerated configs in KMSAN builds to prevent false positive reports. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Idb2334bf3a1b68b31b399709bae= faa763038cc50 --- crypto/Kconfig | 30 ++++++++++++++++++++++++++++++ drivers/net/Kconfig | 1 + 2 files changed, 31 insertions(+) diff --git a/crypto/Kconfig b/crypto/Kconfig index 442765219c375..c5e1c86043bbf 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -290,6 +290,7 @@ config CRYPTO_CURVE25519 config CRYPTO_CURVE25519_X86 tristate "x86_64 accelerated Curve25519 scalar multiplication library" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_LIB_CURVE25519_GENERIC select CRYPTO_ARCH_HAVE_LIB_CURVE25519 =20 @@ -338,11 +339,13 @@ config CRYPTO_AEGIS128 config CRYPTO_AEGIS128_SIMD bool "Support SIMD acceleration for AEGIS-128" depends on CRYPTO_AEGIS128 && ((ARM || ARM64) && KERNEL_MODE_NEON) + depends on !KMSAN # avoid false positives from assembly default y =20 config CRYPTO_AEGIS128_AESNI_SSE2 tristate "AEGIS-128 AEAD algorithm (x86_64 AESNI+SSE2 implementation)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_AEAD select CRYPTO_SIMD help @@ -478,6 +481,7 @@ config CRYPTO_NHPOLY1305 config CRYPTO_NHPOLY1305_SSE2 tristate "NHPoly1305 hash function (x86_64 SSE2 implementation)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_NHPOLY1305 help SSE2 optimized implementation of the hash function used by the @@ -486,6 +490,7 @@ config CRYPTO_NHPOLY1305_SSE2 config CRYPTO_NHPOLY1305_AVX2 tristate "NHPoly1305 hash function (x86_64 AVX2 implementation)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_NHPOLY1305 help AVX2 optimized implementation of the hash function used by the @@ -599,6 +604,7 @@ config CRYPTO_CRC32C config CRYPTO_CRC32C_INTEL tristate "CRC32c INTEL hardware acceleration" depends on X86 + depends on !KMSAN # avoid false positives from assembly select CRYPTO_HASH help In Intel processor with SSE4.2 supported, the processor will @@ -639,6 +645,7 @@ config CRYPTO_CRC32 config CRYPTO_CRC32_PCLMUL tristate "CRC32 PCLMULQDQ hardware acceleration" depends on X86 + depends on !KMSAN # avoid false positives from assembly select CRYPTO_HASH select CRC32 help @@ -704,6 +711,7 @@ config CRYPTO_BLAKE2S config CRYPTO_BLAKE2S_X86 tristate "BLAKE2s digest algorithm (x86 accelerated version)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_LIB_BLAKE2S_GENERIC select CRYPTO_ARCH_HAVE_LIB_BLAKE2S =20 @@ -718,6 +726,7 @@ config CRYPTO_CRCT10DIF config CRYPTO_CRCT10DIF_PCLMUL tristate "CRCT10DIF PCLMULQDQ hardware acceleration" depends on X86 && 64BIT && CRC_T10DIF + depends on !KMSAN # avoid false positives from assembly select CRYPTO_HASH help For x86_64 processors with SSE4.2 and PCLMULQDQ supported, @@ -765,6 +774,7 @@ config CRYPTO_POLY1305 config CRYPTO_POLY1305_X86_64 tristate "Poly1305 authenticator algorithm (x86_64/SSE2/AVX2)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_LIB_POLY1305_GENERIC select CRYPTO_ARCH_HAVE_LIB_POLY1305 help @@ -853,6 +863,7 @@ config CRYPTO_SHA1 config CRYPTO_SHA1_SSSE3 tristate "SHA1 digest algorithm (SSSE3/AVX/AVX2/SHA-NI)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SHA1 select CRYPTO_HASH help @@ -864,6 +875,7 @@ config CRYPTO_SHA1_SSSE3 config CRYPTO_SHA256_SSSE3 tristate "SHA256 digest algorithm (SSSE3/AVX/AVX2/SHA-NI)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SHA256 select CRYPTO_HASH help @@ -876,6 +888,7 @@ config CRYPTO_SHA256_SSSE3 config CRYPTO_SHA512_SSSE3 tristate "SHA512 digest algorithm (SSSE3/AVX/AVX2)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SHA512 select CRYPTO_HASH help @@ -1034,6 +1047,7 @@ config CRYPTO_WP512 config CRYPTO_GHASH_CLMUL_NI_INTEL tristate "GHASH hash function (CLMUL-NI accelerated)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_CRYPTD help This is the x86_64 CLMUL-NI accelerated implementation of @@ -1084,6 +1098,7 @@ config CRYPTO_AES_TI config CRYPTO_AES_NI_INTEL tristate "AES cipher algorithms (AES-NI)" depends on X86 + depends on !KMSAN # avoid false positives from assembly select CRYPTO_AEAD select CRYPTO_LIB_AES select CRYPTO_ALGAPI @@ -1208,6 +1223,7 @@ config CRYPTO_BLOWFISH_COMMON config CRYPTO_BLOWFISH_X86_64 tristate "Blowfish cipher algorithm (x86_64)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SKCIPHER select CRYPTO_BLOWFISH_COMMON imply CRYPTO_CTR @@ -1238,6 +1254,7 @@ config CRYPTO_CAMELLIA config CRYPTO_CAMELLIA_X86_64 tristate "Camellia cipher algorithm (x86_64)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SKCIPHER imply CRYPTO_CTR help @@ -1254,6 +1271,7 @@ config CRYPTO_CAMELLIA_X86_64 config CRYPTO_CAMELLIA_AESNI_AVX_X86_64 tristate "Camellia cipher algorithm (x86_64/AES-NI/AVX)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SKCIPHER select CRYPTO_CAMELLIA_X86_64 select CRYPTO_SIMD @@ -1272,6 +1290,7 @@ config CRYPTO_CAMELLIA_AESNI_AVX_X86_64 config CRYPTO_CAMELLIA_AESNI_AVX2_X86_64 tristate "Camellia cipher algorithm (x86_64/AES-NI/AVX2)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_CAMELLIA_AESNI_AVX_X86_64 help Camellia cipher algorithm module (x86_64/AES-NI/AVX2). @@ -1317,6 +1336,7 @@ config CRYPTO_CAST5 config CRYPTO_CAST5_AVX_X86_64 tristate "CAST5 (CAST-128) cipher algorithm (x86_64/AVX)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SKCIPHER select CRYPTO_CAST5 select CRYPTO_CAST_COMMON @@ -1340,6 +1360,7 @@ config CRYPTO_CAST6 config CRYPTO_CAST6_AVX_X86_64 tristate "CAST6 (CAST-256) cipher algorithm (x86_64/AVX)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SKCIPHER select CRYPTO_CAST6 select CRYPTO_CAST_COMMON @@ -1373,6 +1394,7 @@ config CRYPTO_DES_SPARC64 config CRYPTO_DES3_EDE_X86_64 tristate "Triple DES EDE cipher algorithm (x86-64)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SKCIPHER select CRYPTO_LIB_DES imply CRYPTO_CTR @@ -1430,6 +1452,7 @@ config CRYPTO_CHACHA20 config CRYPTO_CHACHA20_X86_64 tristate "ChaCha stream cipher algorithms (x86_64/SSSE3/AVX2/AVX-512VL)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SKCIPHER select CRYPTO_LIB_CHACHA_GENERIC select CRYPTO_ARCH_HAVE_LIB_CHACHA @@ -1473,6 +1496,7 @@ config CRYPTO_SERPENT config CRYPTO_SERPENT_SSE2_X86_64 tristate "Serpent cipher algorithm (x86_64/SSE2)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SKCIPHER select CRYPTO_SERPENT select CRYPTO_SIMD @@ -1492,6 +1516,7 @@ config CRYPTO_SERPENT_SSE2_X86_64 config CRYPTO_SERPENT_SSE2_586 tristate "Serpent cipher algorithm (i586/SSE2)" depends on X86 && !64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SKCIPHER select CRYPTO_SERPENT select CRYPTO_SIMD @@ -1511,6 +1536,7 @@ config CRYPTO_SERPENT_SSE2_586 config CRYPTO_SERPENT_AVX_X86_64 tristate "Serpent cipher algorithm (x86_64/AVX)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SKCIPHER select CRYPTO_SERPENT select CRYPTO_SIMD @@ -1531,6 +1557,7 @@ config CRYPTO_SERPENT_AVX_X86_64 config CRYPTO_SERPENT_AVX2_X86_64 tristate "Serpent cipher algorithm (x86_64/AVX2)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SERPENT_AVX_X86_64 help Serpent cipher algorithm, by Anderson, Biham & Knudsen. @@ -1672,6 +1699,7 @@ config CRYPTO_TWOFISH_586 config CRYPTO_TWOFISH_X86_64 tristate "Twofish cipher algorithm (x86_64)" depends on (X86 || UML_X86) && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_ALGAPI select CRYPTO_TWOFISH_COMMON imply CRYPTO_CTR @@ -1689,6 +1717,7 @@ config CRYPTO_TWOFISH_X86_64 config CRYPTO_TWOFISH_X86_64_3WAY tristate "Twofish cipher algorithm (x86_64, 3-way parallel)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SKCIPHER select CRYPTO_TWOFISH_COMMON select CRYPTO_TWOFISH_X86_64 @@ -1709,6 +1738,7 @@ config CRYPTO_TWOFISH_X86_64_3WAY config CRYPTO_TWOFISH_AVX_X86_64 tristate "Twofish cipher algorithm (x86_64/AVX)" depends on X86 && 64BIT + depends on !KMSAN # avoid false positives from assembly select CRYPTO_SKCIPHER select CRYPTO_SIMD select CRYPTO_TWOFISH_COMMON diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index b2a4f998c180e..fed89b6981759 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -76,6 +76,7 @@ config WIREGUARD tristate "WireGuard secure network tunnel" depends on NET && INET depends on IPV6 || !IPV6 + depends on !KMSAN # KMSAN doesn't support the crypto configs below select NET_UDP_TUNNEL select DST_CACHE select CRYPTO --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CCDFCC433F5 for ; Tue, 29 Mar 2022 12:46:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236643AbiC2Mre (ORCPT ); Tue, 29 Mar 2022 08:47:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34470 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236175AbiC2MrA (ORCPT ); Tue, 29 Mar 2022 08:47:00 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8558823D763 for ; Tue, 29 Mar 2022 05:42:02 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id k16-20020a17090632d000b006ae1cdb0f07so8118089ejk.16 for ; Tue, 29 Mar 2022 05:42:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=g4O/g3yGtjFTnRq6Tym+8EhZXJHjgp/RAJrohmerxSE=; b=qOFgBTIRaBAgytLmSPVdMFIKWup6qEgqCTL9zlLnfBr+1qisKGAs7mZQzS5fF1N0/w 75BSqMadVv+ZwN4R/Y1880VwCu1sYPXecdfh1+jci1QJBCu4bN2ZpoxrkGg5fNAeuw4/ uqe7fS8vFdcz0MK3boRrEmswcahRoIs30mkNDrxgpAlwqh22khuALzbXXL7Bb57cf0og bNlPI0uZOKQd1VXKE1IEuIH6YQWnxA8v5sTwzz+4zJH90L3gpVOfXta50Pkpjz1H1DCt 0Gsp0BrH+su3tpLOFauLfvXBA1RwcNoUCkd+jh5ebsHf0jr1Db/zRDrg1iivqcmqkSXF Zf4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=g4O/g3yGtjFTnRq6Tym+8EhZXJHjgp/RAJrohmerxSE=; b=bHhrlyjeHkq7ExyNq6YxtlOMKEwXEeEqbiDGoeUATDRxjigfahQLijjEhaDYvsYQgw B6QPA9lSaHXCo/zRayz/jJPL0CL3vClmSuT9yxP/KrRFx1l+T9XSLMfyOEruvbPI+/4P DJFaPSRFZsr1Ur2f7ei4+2nvaJAuI0JY+ztqSk7LlyoPJOJHLkufH+pGV3JZ1wxLg2rZ YR71KPzPN/XVYA9ig5Ikj3kyRgYEDlI3OpoYNp/REZ/jxwDBV4veb9IyejwH35Zx17ui ClSWVRWobFOxRjmZTndKn1s6BTHcbsorgI+8/cWeaSd1DOpbjXiM6ynEoJlgkAAClTI+ A/Tg== X-Gm-Message-State: AOAM533JLXIEer1QnmwniRkd972AUCuju/W+VZ5MoUS2xaU1EfStW0Uc XIqcGI/66cFbNLXtyECPLBZgZSuIAl8= X-Google-Smtp-Source: ABdhPJxPAPS1bh/Xpqng2jeIO39gOYiCpSBLkakMLcyM6oP3/B0k9R3pYWtakO+RdreM9L/Qpt7ZGcmIJWk= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:da6:b0:6e0:c59:f3ad with SMTP id go38-20020a1709070da600b006e00c59f3admr34366333ejc.85.1648557720656; Tue, 29 Mar 2022 05:42:00 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:03 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-35-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 34/48] kmsan: disable physical page merging in biovec From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KMSAN metadata for adjacent physical pages may not be adjacent, therefore accessing such pages together may lead to metadata corruption. We disable merging pages in biovec to prevent such corruptions. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Iece16041be5ee47904fbc98121b= 105e5be5fea5c --- block/blk.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/block/blk.h b/block/blk.h index 8bd43b3ad33d5..eb349916ac116 100644 --- a/block/blk.h +++ b/block/blk.h @@ -93,6 +93,13 @@ static inline bool biovec_phys_mergeable(struct request_= queue *q, phys_addr_t addr1 =3D page_to_phys(vec1->bv_page) + vec1->bv_offset; phys_addr_t addr2 =3D page_to_phys(vec2->bv_page) + vec2->bv_offset; =20 + /* + * Merging adjacent physical pages may not work correctly under KMSAN + * if their metadata pages aren't adjacent. Just disable merging. + */ + if (IS_ENABLED(CONFIG_KMSAN)) + return false; + if (addr1 + vec1->bv_len !=3D addr2) return false; if (xen_domain() && !xen_biovec_phys_mergeable(vec1, vec2->bv_page)) --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25DAEC433F5 for ; Tue, 29 Mar 2022 12:48:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235979AbiC2Mti (ORCPT ); Tue, 29 Mar 2022 08:49:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236705AbiC2MrA (ORCPT ); Tue, 29 Mar 2022 08:47:00 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38D2425279E for ; Tue, 29 Mar 2022 05:42:04 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id do20-20020a170906c11400b006e0de97a0e9so3084421ejc.19 for ; Tue, 29 Mar 2022 05:42:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=/KmrLQz2B9LUGG5T0s5DB1smaxsYg6k7avQ3Zjj3eGk=; b=nf15GMhub2RWppTwCYZIrWIlhESGQRfc/W+NIYyqHWkrAY5ZTdWS9tNg5R+WFNEwDR ws+bWlr0jAPjLQgTU8HBYWK/xBDV/+Z4gS8/E0xP18HFUtngLfocVvFSvgaAAKlkp4H3 kXATs/dpgLrmitCYFBWHPxmJvSrUCCPUNzG/KXTkCq2AyohIUvlifgXGdxppP4apBE5A LAliLdtfENt0IXvOlwHuX/jsHQwOwjSPAiUrAj6DAH7RdyI9h/hc7xkf9IhqtKQUhdA7 KWoj2cicXsXsWzrnFpLIgQlZXdwXJns/c+61ORU+3rxi9tyOWn8w7u20i5xnvlynULyv A3iw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=/KmrLQz2B9LUGG5T0s5DB1smaxsYg6k7avQ3Zjj3eGk=; b=Sf0mpoK8WTYNobzTrf8HVHdc+vAPHNiu44ZeGPLwSAqhXHT2EUACiOOu+cMKvR2JkW eNVDVCmtz0G/Wl3odsWdePyMEUJC7Mq3IQJJecQNCFdzqE+bU4Nst2VmgFVLCLcGcZBU N6c6qabwFfHdvkXcJTJWmfgIuhVRinG6p6Nf498iUdYwQDjp0TP+DVHdB47DkMIxuCeb an1vM/pypFtz/Bxw3kY50s9Mj5ERKEU06HesO1UZTonoxrNPQ0Nj4hmRTf6g8O3455WD o+es1wI6hF8vr58ntad6AOfv1sjJQ94ZWaV9zuDbBQRoAC/6RgxH+RripgH7xapvC5mJ OxeQ== X-Gm-Message-State: AOAM533xiYHL4IQc7+5EBy2rK/cbwxwLxE2toRHnDtyKG/y3ll1OttQS 1wDbB+yZYqnLwriVXoGrDIf8v0O/h1g= X-Google-Smtp-Source: ABdhPJxVb0eTOD5/UioVaLlWvIUvUDI3ZO47Rl6mwf+HN91ZLWrwoGAWiWD7v0UD4gilbb/v2zNMV7AgqQo= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:3583:b0:6d1:c07:fac0 with SMTP id o3-20020a170906358300b006d10c07fac0mr34312763ejb.749.1648557723241; Tue, 29 Mar 2022 05:42:03 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:04 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-36-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 35/48] kmsan: block: skip bio block merging logic for KMSAN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Eric Biggers Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KMSAN doesn't allow treating adjacent memory pages as such, if they were allocated by different alloc_pages() calls. The block layer however does so: adjacent pages end up being used together. To prevent this, make page_is_mergeable() return false under KMSAN. Suggested-by: Eric Biggers Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Ie29cc2464c70032347c32ab2a22= e1e7a0b37b905 --- block/bio.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/bio.c b/block/bio.c index 4312a8085396b..3c8806bbe3a81 100644 --- a/block/bio.c +++ b/block/bio.c @@ -808,6 +808,8 @@ static inline bool page_is_mergeable(const struct bio_v= ec *bv, return false; =20 *same_page =3D ((vec_end_addr & PAGE_MASK) =3D=3D page_addr); + if (!*same_page && IS_ENABLED(CONFIG_KMSAN)) + return false; if (*same_page) return true; return (bv->bv_page + bv_end / PAGE_SIZE) =3D=3D (page + off / PAGE_SIZE); --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 866F7C433EF for ; Tue, 29 Mar 2022 12:49:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236766AbiC2Muq (ORCPT ); Tue, 29 Mar 2022 08:50:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34918 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236748AbiC2MrK (ORCPT ); Tue, 29 Mar 2022 08:47:10 -0400 Received: from mail-ed1-x54a.google.com (mail-ed1-x54a.google.com [IPv6:2a00:1450:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0907725719A for ; Tue, 29 Mar 2022 05:42:07 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id m21-20020a50d7d5000000b00418c7e4c2bbso10963961edj.6 for ; Tue, 29 Mar 2022 05:42:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=XAH4acQx+nIWehlAydXzel6kNYbNIXLv2CmwLsxzisk=; b=YpPQVEPURN2ajRY1n46PwqwFtWp7RlcVqb0MoMfwIeS/m0CwFkAlmK9veRToXX/Nh0 b6E4uZScKbMj2h/RFOMhq1XJYUrJq4RW8RMzRp9Z6yBNz7KYsvHe+FzobtEv1SE+z8z0 bBRHxkEnq08sMogy1ImUi3Oswt0oie9fh2FqU81kZAPoJIolXyiL4DuviryqlAYyJ0cl fP2//D93tGjpn2gvBqCfUGSh263yJnEsQm+Ik3DPQuyteuBuA1cheprPsGBkm0p9BeA1 Z+owbpU+GHDWSgeR7eKuS6SEv9VgACxZntokNlAC2HOBzVv0eGiDKuMeIWei48sQH+i1 OfdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=XAH4acQx+nIWehlAydXzel6kNYbNIXLv2CmwLsxzisk=; b=6axhx/te3mhvqdlgtp6vpOCoa7yraIlHcuKxM2Q8Z9Mx3e3bYq2miIosISq99qyKQr EEmI206ycwalQrYk0c08cc8uPPAzZJDdLHE2AlGF1E6dgR2f6tR413KWC2xYVhI/bzuM UHeoq5624fGEU/YectpobB8EpgY5izRzRDe+bXmO+cWGB8d9UzX3HhtRcE3RHDf+ZHWN nvROrSInb1NziWunbtorS04u8nxCwrro89PMCDii/E2QbkQUjP6/3qeHU9EVcHxqUQB0 xyRY5CGx67wkdBrJ5aORMGJG2Bpnge9rS6Ilt+yeyfLvuU4adDvNnzjiUEv7Beyj4ugK +udA== X-Gm-Message-State: AOAM531Jzz9XsVtBGbsa4rTkIjm+m6V2/CCANmm26YGzEHhJUhVGNRQd jG1utsktpM1MsxeCvVZtc9xMekM6+Qk= X-Google-Smtp-Source: ABdhPJw8wyFM62Ut2Sf7rG+vUT6fWVoAt6oG05coCAtugWeflqaBDOLOCgDn81VaIvvOcjBAOP8lwoc0QHY= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:4313:b0:6b8:b3e5:a46 with SMTP id j19-20020a170906431300b006b8b3e50a46mr33446870ejm.417.1648557725791; Tue, 29 Mar 2022 05:42:05 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:05 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-37-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 36/48] kmsan: kcov: unpoison area->list in kcov_remote_area_put() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KMSAN does not instrument kernel/kcov.c for performance reasons (with CONFIG_KCOV=3Dy virtually every place in the kernel invokes kcov instrumentation). Therefore the tool may miss writes from kcov.c that initialize memory. When CONFIG_DEBUG_LIST is enabled, list pointers from kernel/kcov.c are passed to instrumented helpers in lib/list_debug.c, resulting in false positives. To work around these reports, we unpoison the contents of area->list after initializing it. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Ie17f2ee47a7af58f5cdf716d585= ebf0769348a5a --- kernel/kcov.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/kcov.c b/kernel/kcov.c index 36ca640c4f8e7..88ffdddc99ba1 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -152,6 +153,12 @@ static void kcov_remote_area_put(struct kcov_remote_ar= ea *area, INIT_LIST_HEAD(&area->list); area->size =3D size; list_add(&area->list, &kcov_remote_areas); + /* + * KMSAN doesn't instrument this file, so it may not know area->list + * is initialized. Unpoison it explicitly to avoid reports in + * kcov_remote_area_get(). + */ + kmsan_unpoison_memory(&area->list, sizeof(struct list_head)); } =20 static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct tas= k_struct *t) --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99DB0C433F5 for ; Tue, 29 Mar 2022 12:49:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236736AbiC2Mul (ORCPT ); Tue, 29 Mar 2022 08:50:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236749AbiC2MrK (ORCPT ); Tue, 29 Mar 2022 08:47:10 -0400 Received: from mail-ed1-x54a.google.com (mail-ed1-x54a.google.com [IPv6:2a00:1450:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 082802597CC for ; Tue, 29 Mar 2022 05:42:09 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id c31-20020a509fa2000000b004190d43d28fso10861905edf.9 for ; Tue, 29 Mar 2022 05:42:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=hN0px5Y6w+gPiIIsc2Y11OjC7QzplCcP/UQmq/enNWc=; b=Hba3tqo2ZktNSh5VayjCUcXgsuLQihspG9CdbIkgwV0XnzhptRTheqtvOJvtrkRDxi Ss5riSjqs79q4sj6vEzrl9e5NAnMEYkMtOD7DR0kjiXToleB0xMmrngB/lOmVp53Pm6g sL4jzNQgPIYiWPmAUDH+RYqBmhUxqdDakm3uNuUeS06KDhE0eZO/1cXNArkf4IMFhORp upUi5nfSsYrTnu7bITVW1QpAkL5mzKSSvi2xge0Ig/ckS6wgZKchB3Otj/IUHLOME2c5 nfU0OUdtpKDV6uNoZH/AIPbh7jb1irxWmMv0KTxL8c9e0tXERBb3wU1Xna/UfTWWtWS9 xT2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=hN0px5Y6w+gPiIIsc2Y11OjC7QzplCcP/UQmq/enNWc=; b=pAQ6k41NcQSHK6tFHumdvoYFl5kjw59/PcvqFBNA4+i0Tu1/yks3LNaGonPZdK6SCZ POk4YMfbt1I/B/IXhKe3L+XBg50tnF7gZwscVLZzqolfFYfLqFCBZmFMMrqZQXy+RYpE F46rC8x4pdFVuVaHS2CO+GZEEoRFFgXRbz0VMmDXL1MCt88K+z0kVeUSUeUHH4gqgD/H 7ot8xhWlRb+4yT10/TkBmi5yg/k9tt0qTID6Jn6GPt8n4OlWuIU8Hc8xpBSjN0UgyLTf HHCFubAaW0myJ5TQ3Q8qaoXYRsbGusZ+klnf7HlxbycNPcGqzdfRcJf1CXsT3Z+sOus4 0hGA== X-Gm-Message-State: AOAM531G2+ZOcqNfNTPqfw5xI6hceVQGwhvhFWGx6ydGL9kxFpYbzRYb wf1el9QK8AA7PsKY5nJm6J4H0VR8aDs= X-Google-Smtp-Source: ABdhPJw+mVHIQcKBP/V+6lL9kzLF8SImygn1gNkK6rHWczIwHLyPFu9Mt2wT/36dHdaMhbuj9deBSL0XS6g= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a05:6402:1e8b:b0:3da:58e6:9a09 with SMTP id f11-20020a0564021e8b00b003da58e69a09mr4276833edf.155.1648557728308; Tue, 29 Mar 2022 05:42:08 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:06 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-38-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 37/48] security: kmsan: fix interoperability with auto-initialization From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Heap and stack initialization is great, but not when we are trying uses of uninitialized memory. When the kernel is built with KMSAN, having kernel memory initialization enabled may introduce false negatives. We disable CONFIG_INIT_STACK_ALL_PATTERN and CONFIG_INIT_STACK_ALL_ZERO under CONFIG_KMSAN, making it impossible to auto-initialize stack variables in KMSAN builds. We also disable CONFIG_INIT_ON_ALLOC_DEFAULT_ON and CONFIG_INIT_ON_FREE_DEFAULT_ON to prevent accidental use of heap auto-initialization. We however still let the users enable heap auto-initialization at boot-time (by setting init_on_alloc=3D1 or init_on_free=3D1), in which case a warning is printed. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I86608dd867018683a14ae1870f1= 928ad925f42e9 --- mm/page_alloc.c | 4 ++++ security/Kconfig.hardening | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 4237b7290e619..ef0906296c57f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -868,6 +868,10 @@ void init_mem_debugging_and_hardening(void) else static_branch_disable(&init_on_free); =20 + if (IS_ENABLED(CONFIG_KMSAN) && + (_init_on_alloc_enabled_early || _init_on_free_enabled_early)) + pr_info("mem auto-init: please make sure init_on_alloc and init_on_free = are disabled when running KMSAN\n"); + #ifdef CONFIG_DEBUG_PAGEALLOC if (!debug_pagealloc_enabled()) return; diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index d051f8ceefddd..bd13a46024457 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -106,6 +106,7 @@ choice config INIT_STACK_ALL_PATTERN bool "pattern-init everything (strongest)" depends on CC_HAS_AUTO_VAR_INIT_PATTERN + depends on !KMSAN help Initializes everything on the stack (including padding) with a specific debug value. This is intended to eliminate @@ -124,6 +125,7 @@ choice config INIT_STACK_ALL_ZERO bool "zero-init everything (strongest and safest)" depends on CC_HAS_AUTO_VAR_INIT_ZERO + depends on !KMSAN help Initializes everything on the stack (including padding) with a zero value. This is intended to eliminate all @@ -208,6 +210,7 @@ config STACKLEAK_RUNTIME_DISABLE =20 config INIT_ON_ALLOC_DEFAULT_ON bool "Enable heap memory zeroing on allocation by default" + depends on !KMSAN help This has the effect of setting "init_on_alloc=3D1" on the kernel command line. This can be disabled with "init_on_alloc=3D0". @@ -220,6 +223,7 @@ config INIT_ON_ALLOC_DEFAULT_ON =20 config INIT_ON_FREE_DEFAULT_ON bool "Enable heap memory zeroing on free by default" + depends on !KMSAN help This has the effect of setting "init_on_free=3D1" on the kernel command line. This can be disabled with "init_on_free=3D0". --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1EA84C433F5 for ; Tue, 29 Mar 2022 12:49:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236832AbiC2Mvb (ORCPT ); Tue, 29 Mar 2022 08:51:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236682AbiC2MrY (ORCPT ); Tue, 29 Mar 2022 08:47:24 -0400 Received: from mail-ej1-x64a.google.com (mail-ej1-x64a.google.com [IPv6:2a00:1450:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 679BF25AED8 for ; Tue, 29 Mar 2022 05:42:12 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id gv17-20020a1709072bd100b006dfcc7f7962so8126808ejc.5 for ; Tue, 29 Mar 2022 05:42:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=T39GYI/vBjMdfMtH+Dx38ArgDU/LjDSVRO95NSUKYys=; b=Ga2g0KSm7zN5HCLMp88eZDrOW0thBYZOgl2SJsxhqq1/9JhR9hzR13gng3zeCxso+w i/qtco4gzCEgnTlb2mhL9BTKSiQMQJdKNozm6n1+hL+sDqOwULwTLCdwyrZELS+NA7W/ c5qB98YvHHLJ3BMBq1pJMPQpE9RNLyE4eXN+o9MmFC6t7LQ+u14xMMOIVA+bA5naY+8s gRNrHJavp3e4jVaVQltJlMKiFbXubOTSrISRSTmFuJe4c/qmXIPakHSoPpaD9bKOA9pq oeNXL7OnbYXNrhPT7iXlkE3Z7JYvDzAHoBqV8prd4N81xr62OjBryDQm9qe/C7bS4tTD qDsQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=T39GYI/vBjMdfMtH+Dx38ArgDU/LjDSVRO95NSUKYys=; b=jNFsoix5iw1S6i3FwzMS522PLvipWtngG8rhCQwAL+zItUpvBPeb6R+9V50ovmQuH6 edYa5YI1/vo1/8TWwtmHdCHBwIe3zK1y+whY2kE1FdGEZueNnJpgRtrHNPvgxksT3RmP jcnRRviYp1kJhuhkTp6l/qd1lLkBqLkdh1sfPgzx8Er9pJ+pLzK39f5qlLYX5mkRGbJT CbOaHlOakNl6vxnGxYYs6piuTw7zxDPzCi8/usBEdynLJyKz5TuBTr93j8xclSitk6Z7 DszNpysBSLPczrJAqLL+8XuMKGnYS+94F6VfCLiH2rWtcM/MXHWAEorVa1O5mn2UayKh fl5g== X-Gm-Message-State: AOAM533F1rA/brQj0DaHQ443GKUAmyTGKWGgQ4BF3m6IX7qGQ0D786Mw ANnaWfaBy9BRADZ0Sc/uuJO25jpBdVs= X-Google-Smtp-Source: ABdhPJxnAD1WnRha3aT8bQpiv1ryLHN37wPgdzyd6u5jtCYTidxo5YWhjtFuZMhdjM/eFbjpolf6XzG13+Y= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:1ca4:b0:6da:86a4:1ec7 with SMTP id nb36-20020a1709071ca400b006da86a41ec7mr34900718ejc.556.1648557730788; Tue, 29 Mar 2022 05:42:10 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:07 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-39-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 38/48] objtool: kmsan: list KMSAN API functions as uaccess-safe From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KMSAN inserts API function calls in a lot of places (function entries and exits, local variables, memory accesses), so they may get called from the uaccess regions as well. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I242bc9816273fecad4ea3d97739= 3784396bb3c35 --- tools/objtool/check.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 7c33ec67c4a95..8518eaf05bff0 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -943,6 +943,25 @@ static const char *uaccess_safe_builtin[] =3D { "__sanitizer_cov_trace_cmp4", "__sanitizer_cov_trace_cmp8", "__sanitizer_cov_trace_switch", + /* KMSAN */ + "kmsan_copy_to_user", + "kmsan_report", + "kmsan_unpoison_memory", + "__msan_chain_origin", + "__msan_get_context_state", + "__msan_instrument_asm_store", + "__msan_metadata_ptr_for_load_1", + "__msan_metadata_ptr_for_load_2", + "__msan_metadata_ptr_for_load_4", + "__msan_metadata_ptr_for_load_8", + "__msan_metadata_ptr_for_load_n", + "__msan_metadata_ptr_for_store_1", + "__msan_metadata_ptr_for_store_2", + "__msan_metadata_ptr_for_store_4", + "__msan_metadata_ptr_for_store_8", + "__msan_metadata_ptr_for_store_n", + "__msan_poison_alloca", + "__msan_warning", /* UBSAN */ "ubsan_type_mismatch_common", "__ubsan_handle_type_mismatch", --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2237C433F5 for ; Tue, 29 Mar 2022 12:48:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236655AbiC2Mtu (ORCPT ); Tue, 29 Mar 2022 08:49:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236740AbiC2Mr0 (ORCPT ); Tue, 29 Mar 2022 08:47:26 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1AA3321BC52 for ; Tue, 29 Mar 2022 05:42:15 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id hg13-20020a1709072ccd00b006dfa484ec23so8157040ejc.8 for ; Tue, 29 Mar 2022 05:42:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=vfNewWnsnLKjgrLxloInM3ksKktMuhZ88Cjjen8dSfw=; b=k2grIaWEX10+pjmxqhkcyCA78d3h23qdz2hQwriW/AtBkEbXWlTAWHSjR5jVjwbRd0 HKX1zG6uUcVNaozu8WxucSiCuQwHnnudt3nW2uxWtac7hF54EJ1kbSIlqPv4TwsjdCTr G92SqYktPjAwRps3tSeMbzJyGmoMawImGJXnVDm7RQbHHOMHmWqFKxMC2IeRQOg1Xhxq OJFN3e7mKc2NOaXlMGXsa9yHEVB8W3tfRWFhpSrRETeApxMNk01V3f1Rz7tcgby1LDeH XGjGGEIIihzXVuI4E4ZD/omsJ5xBfcLQ6Erf+tZ7ZaeE1xczews93WWLLOk7DrdHF6hz Ns5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=vfNewWnsnLKjgrLxloInM3ksKktMuhZ88Cjjen8dSfw=; b=vq81z/lVVJ1gcJoID8do64tmXfvjqsbfh5vFmtRCKeqInxawnsvRk/eNsa/wiyOCbY q8/NARCWQlelZLgI/WhH0kNmGqDz7UxIln8a9n5+zOPCDC25HWrjCH7/frI4+vbCXKef zOMY8HQta7iJK+dQ2q2mtQfJ7tyzCxKvhKFMZB4yZugWtP43JOnTfHKyGj10Y7VkkQRS OpRcqsjXfXQ6qlN+fu3Yrj+sjvy1DmDjhG4sfQ227wRdsSQx8b2qGA1Or1GLVoj4ilKn CoDGlItkdMtf1qL8metLXejkiQNbsw2qrHQFJjF+KjPxcO1iPqKvMIu5FCsQCtjGsL/X Cexg== X-Gm-Message-State: AOAM532L3OgElDqWOq+KG+oNy2BkBVIYDEO2HWi+3BMYlrYCDCoydo4g MgakP2BF+XoDn+CM0CiHt64xkycqFWY= X-Google-Smtp-Source: ABdhPJxYhi4C5lMRGBP4ot4j5u4X+r6OfqpTJ+iIL9kMkH3POTY1BlEuc6eV3fFfpCDp3jcSR0ZuHMnxazU= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:2699:b0:6d0:9f3b:a6a7 with SMTP id t25-20020a170906269900b006d09f3ba6a7mr33007227ejc.397.1648557733360; Tue, 29 Mar 2022 05:42:13 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:08 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-40-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 39/48] x86: kmsan: make READ_ONCE_TASK_STACK() return initialized values From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" To avoid false positives, assume that reading from the task stack always produces initialized values. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I9e2350bf3e88688dd83537e12a2= 3456480141997 --- arch/x86/include/asm/unwind.h | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h index 2a1f8734416dc..51173b19ac4d5 100644 --- a/arch/x86/include/asm/unwind.h +++ b/arch/x86/include/asm/unwind.h @@ -129,18 +129,19 @@ unsigned long unwind_recover_ret_addr(struct unwind_s= tate *state, } =20 /* - * This disables KASAN checking when reading a value from another task's s= tack, - * since the other task could be running on another CPU and could have poi= soned - * the stack in the meantime. + * This disables KASAN/KMSAN checking when reading a value from another ta= sk's + * stack, since the other task could be running on another CPU and could h= ave + * poisoned the stack in the meantime. Frame pointers are uninitialized by + * default, so for KMSAN we mark the return value initialized unconditiona= lly. */ -#define READ_ONCE_TASK_STACK(task, x) \ -({ \ - unsigned long val; \ - if (task =3D=3D current) \ - val =3D READ_ONCE(x); \ - else \ - val =3D READ_ONCE_NOCHECK(x); \ - val; \ +#define READ_ONCE_TASK_STACK(task, x) \ +({ \ + unsigned long val; \ + if (task =3D=3D current && !IS_ENABLED(CONFIG_KMSAN)) \ + val =3D READ_ONCE(x); \ + else \ + val =3D READ_ONCE_NOCHECK(x); \ + val; \ }) =20 static inline bool task_on_another_cpu(struct task_struct *task) --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74559C433EF for ; Tue, 29 Mar 2022 12:49:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236890AbiC2MvF (ORCPT ); Tue, 29 Mar 2022 08:51:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53084 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236756AbiC2Mr2 (ORCPT ); Tue, 29 Mar 2022 08:47:28 -0400 Received: from mail-ej1-x64a.google.com (mail-ej1-x64a.google.com [IPv6:2a00:1450:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A7AA25C59F for ; Tue, 29 Mar 2022 05:42:17 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id og28-20020a1709071ddc00b006dfb92d8e3fso8110868ejc.14 for ; Tue, 29 Mar 2022 05:42:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=06dyFy4NZEX890kyFUV8Iv1YE1gnoJOMR7Gzlteh8jY=; b=Q2viYIJcVvUQijU4U9D1Dj2AFiuH23Eb1Cg6kjs6VZINfQ//kbrjiRJ1yRFJzKaL95 tQJlNRbpesfMyVc/wyOht/HynqAFff9Su6k44SSjUB8e2ASIhP69zbj05HIMXeK6L1OL ySYUfvObdacOc2wdAG0IyYrl2RHLnydnHHmfzRRrcKEWnpWTcd8jHV+TE7DNEa1UCekz 6KJVzVYtGJ3IVan1hIEN3NujxMnzK82nblY1rg0IK6jZi+5p1Rf4+CXyXuOLIkxIKFLO 1LM1HLYTxGIOL5VXdKr2d8uHtUFahOWpwBd/6N2sHJ5/7Wh6V+e3Ncbzfm+da1hhXAXU 5dTQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=06dyFy4NZEX890kyFUV8Iv1YE1gnoJOMR7Gzlteh8jY=; b=tW3xhVHgjyBbN5/Vj5rS0TdNxqC525lv7dCAfhfPhSyjYV4X8WbFvdNH+O/X5BwW2D +43dsfivDyC6mvGNgQLiw0VwW5YmMy3Rns6X8F3DKPu1sHxIzOhLUsxx5WCWjQv4DFTO 4NJ6uBYdS/Z79OG5uXSKMlMkKETNCA1ZYC0DTP1wKAuZDf2r9VvirFgTC6w8zbBJpRkE yuPvgCOTSusp82+vtyQKdVWSZTH4e/8SHC9rIiHV24NiyVNbgu7Jh2CBL6nJsJ6l1BIy dmAIJGhLHm+M+scNX5oR33zEQ1HO/318ktfHJDvj88rhAmexC6Ah+B9H6pHQSDLdhcAj kpDg== X-Gm-Message-State: AOAM532bpiavFkTw6V6s+saDzbPOA+9CSkn9WqGHjOEzqXF4sW4LDQBF Pxz3tBaRQ3G6IeMDDUb+aHcXJUhrG0A= X-Google-Smtp-Source: ABdhPJyK+xCDqG5EBgv8UrRhuZ4ui8rzuRpy41w829H2Gd00Q0wKOzSf8/FZHSjDv6y2E59F+2K0K4M0Fus= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:57c1:b0:6d6:da73:e9c0 with SMTP id u1-20020a17090657c100b006d6da73e9c0mr35219641ejr.45.1648557735848; Tue, 29 Mar 2022 05:42:15 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:09 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-41-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 40/48] x86: kmsan: disable instrumentation of unsupported code From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Instrumenting some files with KMSAN will result in kernel being unable to link, boot or crashing at runtime for various reasons (e.g. infinite recursion caused by instrumentation hooks calling instrumented code again). Completely omit KMSAN instrumentation in the following places: - arch/x86/boot and arch/x86/realmode/rm, as KMSAN doesn't work for i386; - arch/x86/entry/vdso, which isn't linked with KMSAN runtime; - three files in arch/x86/kernel - boot problems; - arch/x86/mm/cpu_entry_area.c - recursion. Signed-off-by: Alexander Potapenko --- v2: - moved the patch earlier in the series so that KMSAN can compile - split off the non-x86 part into a separate patch Link: https://linux-review.googlesource.com/id/Id5e5c4a9f9d53c24a35ebb633b8= 14c414628d81b --- arch/x86/boot/Makefile | 1 + arch/x86/boot/compressed/Makefile | 1 + arch/x86/entry/vdso/Makefile | 3 +++ arch/x86/kernel/Makefile | 2 ++ arch/x86/kernel/cpu/Makefile | 1 + arch/x86/mm/Makefile | 2 ++ arch/x86/realmode/rm/Makefile | 1 + 7 files changed, 11 insertions(+) diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index b5aecb524a8aa..d5623232b763f 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -12,6 +12,7 @@ # Sanitizer runtimes are unavailable and cannot be linked for early boot c= ode. KASAN_SANITIZE :=3D n KCSAN_SANITIZE :=3D n +KMSAN_SANITIZE :=3D n OBJECT_FILES_NON_STANDARD :=3D y =20 # Kernel does not boot with kcov instrumentation here. diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/M= akefile index 6115274fe10fc..6e2e34d2655ce 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -20,6 +20,7 @@ # Sanitizer runtimes are unavailable and cannot be linked for early boot c= ode. KASAN_SANITIZE :=3D n KCSAN_SANITIZE :=3D n +KMSAN_SANITIZE :=3D n OBJECT_FILES_NON_STANDARD :=3D y =20 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 693f8b9031fb8..4f835eaa03ec1 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -11,6 +11,9 @@ include $(srctree)/lib/vdso/Makefile =20 # Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE :=3D n +KMSAN_SANITIZE_vclock_gettime.o :=3D n +KMSAN_SANITIZE_vgetcpu.o :=3D n + UBSAN_SANITIZE :=3D n KCSAN_SANITIZE :=3D n OBJECT_FILES_NON_STANDARD :=3D y diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 6aef9ee28a394..ad645fb8b02dd 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -35,6 +35,8 @@ KASAN_SANITIZE_cc_platform.o :=3D n # With some compiler versions the generated code results in boot hangs, ca= used # by several compilation units. To be safe, disable all instrumentation. KCSAN_SANITIZE :=3D n +KMSAN_SANITIZE_head$(BITS).o :=3D n +KMSAN_SANITIZE_nmi.o :=3D n =20 OBJECT_FILES_NON_STANDARD_test_nx.o :=3D y =20 diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index 9661e3e802be5..f10a921ee7565 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -12,6 +12,7 @@ endif # If these files are instrumented, boot hangs during the first second. KCOV_INSTRUMENT_common.o :=3D n KCOV_INSTRUMENT_perf_event.o :=3D n +KMSAN_SANITIZE_common.o :=3D n =20 # As above, instrumenting secondary CPU boot code causes boot hangs. KCSAN_SANITIZE_common.o :=3D n diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile index fe3d3061fc116..ada726784012f 100644 --- a/arch/x86/mm/Makefile +++ b/arch/x86/mm/Makefile @@ -12,6 +12,8 @@ KASAN_SANITIZE_mem_encrypt_identity.o :=3D n # Disable KCSAN entirely, because otherwise we get warnings that some func= tions # reference __initdata sections. KCSAN_SANITIZE :=3D n +# Avoid recursion by not calling KMSAN hooks for CEA code. +KMSAN_SANITIZE_cpu_entry_area.o :=3D n =20 ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_mem_encrypt.o =3D -pg diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile index 83f1b6a56449f..f614009d3e4e2 100644 --- a/arch/x86/realmode/rm/Makefile +++ b/arch/x86/realmode/rm/Makefile @@ -10,6 +10,7 @@ # Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE :=3D n KCSAN_SANITIZE :=3D n +KMSAN_SANITIZE :=3D n OBJECT_FILES_NON_STANDARD :=3D y =20 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD776C433EF for ; Tue, 29 Mar 2022 12:49:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236826AbiC2MvY (ORCPT ); Tue, 29 Mar 2022 08:51:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236812AbiC2MsG (ORCPT ); Tue, 29 Mar 2022 08:48:06 -0400 Received: from mail-ej1-x64a.google.com (mail-ej1-x64a.google.com [IPv6:2a00:1450:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1954225CB98 for ; Tue, 29 Mar 2022 05:42:20 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id h22-20020a1709060f5600b006b11a2d3dcfso8126847ejj.4 for ; Tue, 29 Mar 2022 05:42:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=eekKcS683P9sWiTSuhgkvdPXp9EdJwN5ZjFsPJMzm7E=; b=nThiYlFFBsJrC6J4CsRmdsKff+pDAxmWAIIBI48Vo80VmKhgV7dastoHrc6SVW9X6d jx/eMpAi1+TKGKqks/kz1GydwiVFtB3s4/Iqslz0Sb0I1p4yER6QQnh5/UL9bNG2RLeo C5XtiIVh5zpbhTTlL5airTyDdq93mQxCRjBtLqk2mbuMHgpMJxTKy/8BxllO8FXvoXri ekBImg/blQGPTzvxUnzHyySXJs6MIGJ9C3qLF6RA9zgxjyAbLcaI48UrWAydgcCoo14J kueGk3ukqrtHmHCvYLUUERRZzvhgDhUfNxGvcRCiVUwTYx9WsgjVrySPvU/5ycGH8wZP hUMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=eekKcS683P9sWiTSuhgkvdPXp9EdJwN5ZjFsPJMzm7E=; b=TJn4ebmQJbPzt8sSkAnkxqLAeKp3nReVtkDvR6ognjWpL+wvA9ySvjDlWjFv5EFysw kTTlRxx/7xP7Nr+cLARB0H6EdkNGFOtrb+GWxdzbhfbHJsrYuAAHZnky8AbVF4wH0J9u weRVe0snq9GNvTohQfmI2LvlvTMFSF+QnGj+x74wBgdKkjv/D1HJ65lV7Ts+xaOsHd4v 7AaGWnRjm+h+hvjQON63bnzmPuSd7lvTCAZv6PDMM3LvOnofPQUcyEWjKvswniBX1w+c jTchsADAXlmQWCQfXs6AmA/7xpjBvUHPhiZ1i45BcyvZZvH7CsIVQL7gJ4NivV94HbQK w6gw== X-Gm-Message-State: AOAM530VbnR7Mt6NfuHJCHXW3h79SSOwMOn9npSe3zQa6b5CiXb3dr9S yh9GPPJ6rqnWBVznoWPAeEnJKJ2q3jo= X-Google-Smtp-Source: ABdhPJzQ+mzPatwMfV3rPhv+G2Q81dnqKFY/srjOhBDb0t1yefVaA5tyYkGIYP5vkw1Slryk14/AH+9Tlek= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a50:c010:0:b0:418:d53c:24ec with SMTP id r16-20020a50c010000000b00418d53c24ecmr4358428edb.17.1648557738276; Tue, 29 Mar 2022 05:42:18 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:10 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-42-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 41/48] x86: kmsan: skip shadow checks in __switch_to() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When instrumenting functions, KMSAN obtains the per-task state (mostly pointers to metadata for function arguments and return values) once per function at its beginning, using the `current` pointer. Every time the instrumented function calls another function, this state (`struct kmsan_context_state`) is updated with shadow/origin data of the passed and returned values. When `current` changes in the low-level arch code, instrumented code can not notice that, and will still refer to the old state, possibly corrupting it or using stale data. This may result in false positive reports. To deal with that, we need to apply __no_kmsan_checks to the functions performing context switching - this will result in skipping all KMSAN shadow checks and marking newly created values as initialized, preventing all false positive reports in those functions. False negatives are still possible, but we expect them to be rare and impersistent. Suggested-by: Marco Elver Signed-off-by: Alexander Potapenko --- v2: -- This patch was previously called "kmsan: skip shadow checks in files doing context switches". Per Mark Rutland's suggestion, we now only skip checks in low-level arch-specific code, as context switches in common code should be invisible to KMSAN. We also apply the checks to precisely the functions performing the context switch instead of the whole file. Link: https://linux-review.googlesource.com/id/I45e3ed9c5f66ee79b0409d1673d= 66ae419029bcb --- arch/x86/kernel/process_64.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 3402edec236c4..838b1e9808d6f 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -553,6 +553,7 @@ void compat_start_thread(struct pt_regs *regs, u32 new_= ip, u32 new_sp, bool x32) * Kprobes not supported here. Set the probe on schedule instead. * Function graph tracer not supported too. */ +__no_kmsan_checks __visible __notrace_funcgraph struct task_struct * __switch_to(struct task_struct *prev_p, struct task_struct *next_p) { --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1EBDC43219 for ; Tue, 29 Mar 2022 12:48:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234229AbiC2Mt7 (ORCPT ); Tue, 29 Mar 2022 08:49:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236831AbiC2MsH (ORCPT ); Tue, 29 Mar 2022 08:48:07 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 758BF224749 for ; Tue, 29 Mar 2022 05:42:22 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id gv17-20020a1709072bd100b006dfcc7f7962so8127026ejc.5 for ; Tue, 29 Mar 2022 05:42:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=6EKMd0bjP1WkGhZZPkjCgU25E3DWfYJCasURW7mFnYs=; b=P1k71GssRqu7HsErV73nnblS85PhkUFheLyBFZgmPWLpl7OKiy1Bqi/JlOtZzfJVPy VAc7cvO8fwjHIxHwD4P9pVu2rdNH8e0p6iE439JugyKP3tEZpAogt6YoEY/b5rvhs6YN OlYMWP+8vwtXjv8eNiLfoejuKaPkdCuMEozoeNlW8PpIb+edtD9db/0+pmWKLdNhwURR 5E3Lth/p8S4d05TzSLze03fVsfkwrT++EyTKtUjOhLVyC4kbo3lKGGRltm0PtD2GB/IH Q3WE4SbVcH6AFhiknkVN5O3R1HMm1J+ZfOcalpdSexIx4dKDpVcT7q34bBD07dT9kvEi C7Fw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=6EKMd0bjP1WkGhZZPkjCgU25E3DWfYJCasURW7mFnYs=; b=rPJuR5MEzyzLKzKLm81Sz3UQ4ii9YtT0rVjc7jime4/vS1Lc6FS7XfhYjvdMyHp7tG 8TCrefZGujaFe/KvRe3mpezAoR6uryr6KnnSqR39RujTzZuY1MpDcvxZzxye2PNmZ9JY iuMAl24Uay7SlUb4HVLni4aRpltGx+XCCkbnpaA/3EeMpky3gX0OA9t6gghNcdvLrjiL pAKSsNZs5e0LoHDoXF9K/HzxB+xGmhSIRTdr3xx+ZswM2Ef5OPXF82KcPSN1J3rVVQR5 GxMNwm6C0Mbka5uIAxGfeZNA11wFb88LA5oMJXMD13WnQNN508K8dTEXxLhNCyQ1lrsc V48g== X-Gm-Message-State: AOAM531a6mAMO552v74Dz5dQ7/9kSOIQEZ+u0GdiMEGzKeDvfmFjng5p nXXgJ4Fh75eV0XTknYf0Qnu1f4XX+GA= X-Google-Smtp-Source: ABdhPJyN/u61iYoRLkPCDJv7Xs3UegKZjTjkx8b5A87Fx1oaelxWk3uqKnX5mytmcMKvTp7b3Wewv/gEEvA= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:3042:b0:6cd:20ed:7c5c with SMTP id d2-20020a170906304200b006cd20ed7c5cmr33818169ejd.241.1648557740796; Tue, 29 Mar 2022 05:42:20 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:11 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-43-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 42/48] x86: kmsan: handle open-coded assembly in lib/iomem.c From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KMSAN cannot intercept memory accesses within asm() statements. That's why we add kmsan_unpoison_memory() and kmsan_check_memory() to hint it how to handle memory copied from/to I/O memory. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Icb16bf17269087e475debf07a7f= e7d4bebc3df23 --- arch/x86/lib/iomem.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/lib/iomem.c b/arch/x86/lib/iomem.c index df50451d94ef7..2307770f3f4c8 100644 --- a/arch/x86/lib/iomem.c +++ b/arch/x86/lib/iomem.c @@ -1,6 +1,7 @@ #include #include #include +#include =20 #define movs(type,to,from) \ asm volatile("movs" type:"=3D&D" (to), "=3D&S" (from):"0" (to), "1" (from= ):"memory") @@ -37,6 +38,8 @@ void memcpy_fromio(void *to, const volatile void __iomem = *from, size_t n) n-=3D2; } rep_movs(to, (const void *)from, n); + /* KMSAN must treat values read from devices as initialized. */ + kmsan_unpoison_memory(to, n); } EXPORT_SYMBOL(memcpy_fromio); =20 @@ -45,6 +48,8 @@ void memcpy_toio(volatile void __iomem *to, const void *f= rom, size_t n) if (unlikely(!n)) return; =20 + /* Make sure uninitialized memory isn't copied to devices. */ + kmsan_check_memory(from, n); /* Align any unaligned destination IO */ if (unlikely(1 & (unsigned long)to)) { movs("b", to, from); --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 745EFC433F5 for ; Tue, 29 Mar 2022 12:48:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236692AbiC2MuY (ORCPT ); Tue, 29 Mar 2022 08:50:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55892 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236848AbiC2MsI (ORCPT ); Tue, 29 Mar 2022 08:48:08 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E82522BD76 for ; Tue, 29 Mar 2022 05:42:25 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id x5-20020a50ba85000000b00418e8ce90ffso10940029ede.14 for ; Tue, 29 Mar 2022 05:42:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=NOfDS0CsOY5h9mAj6JbXzNq92U67NVHjp1LhoXoozQE=; b=Nn0hcJcow4Zi7/qxTCnawsZd86i/kfajgqOZt7a19BzANMrQn3RZVXK/4TSbOgTtKy EZXwKZ2ETjPWwTQI84e+ZS4kCQZicjI4YNLp506aUC1vJIqm4sYJ9Jk00ZDxlbxl+PLB I5mp72VYTHiRMctKwlnD1s+EvmhkJ/kSzPgw4eOi0GnsAWgkzobtSIgiRYb2F6NVLdQr ygOxPLA0uG7pXUYXgxRRYvjcZdbBM+cj+52SkT7eFAPFsazO+XOHu6xCOBRJhGkNlNFY jvJktjAJ2UXDOtvgbcc5Nl2IbozKqFTgnIdEGvzEGMEsOCP/KyQRrmJM8Q+toW8lmnUu BZAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=NOfDS0CsOY5h9mAj6JbXzNq92U67NVHjp1LhoXoozQE=; b=AmN40YSGjszcc2CxwiA4uNjQ1QffYFqjGIYi8+sMmWloSouHDmdN+eo68vWitOYBKq ySeH7tEdMYMgRRUnC7Veny3UxdeyUD/dNsjNmK4NTI8acg7RHDwHm3KpmsZ7erA4rKDs Dv1w6VZ0ToW7XgFef8jkjHo5kDW9JbY579ZSwO9a2Inea5ANVna2deVWFz0Zo89xYROd BTudYXL9pzfkNE2maaGUZN/hLf8vtisNGwEJY7yQciRMQJadIgOnYXjiosFVqIDn/GPv IzIE+wYkfJMQrZMjpPL6lLWcjBKpS+SiHGiCVluhChWid1Tsj2d416Mm+Qs54Cy/5+u+ bSjA== X-Gm-Message-State: AOAM531iC/wspaaiGkaEV1egGR8477JoXQvwa8iN0H7/u8dIlSGFtRYP GBpDwus2noWZ4+WQuLjzBhPGi/5qKKw= X-Google-Smtp-Source: ABdhPJwjvewOCtdgKLCr3b6pMPkXnDTkN3wiCJIAUwFNMFNSlC6T2GR80JxGo48vEzlzJdJxvNcfeTGHeAU= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a05:6402:d72:b0:419:938d:f4ce with SMTP id ec50-20020a0564020d7200b00419938df4cemr4402146edb.166.1648557743423; Tue, 29 Mar 2022 05:42:23 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:12 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-44-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 43/48] x86: kmsan: use __msan_ string functions where possible. From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Unless stated otherwise (by explicitly calling __memcpy(), __memset() or __memmove()) we want all string functions to call their __msan_ versions (e.g. __msan_memcpy() instead of memcpy()), so that shadow and origin values are updated accordingly. Bootloader must still use the default string functions to avoid crashes. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I7ca9bd6b4f5c9b9816404862ae8= 7ca7984395f33 --- arch/x86/include/asm/string_64.h | 23 +++++++++++++++++++++-- include/linux/fortify-string.h | 2 ++ 2 files changed, 23 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string= _64.h index 6e450827f677a..3b87d889b6e16 100644 --- a/arch/x86/include/asm/string_64.h +++ b/arch/x86/include/asm/string_64.h @@ -11,11 +11,23 @@ function. */ =20 #define __HAVE_ARCH_MEMCPY 1 +#if defined(__SANITIZE_MEMORY__) +#undef memcpy +void *__msan_memcpy(void *dst, const void *src, size_t size); +#define memcpy __msan_memcpy +#else extern void *memcpy(void *to, const void *from, size_t len); +#endif extern void *__memcpy(void *to, const void *from, size_t len); =20 #define __HAVE_ARCH_MEMSET +#if defined(__SANITIZE_MEMORY__) +extern void *__msan_memset(void *s, int c, size_t n); +#undef memset +#define memset __msan_memset +#else void *memset(void *s, int c, size_t n); +#endif void *__memset(void *s, int c, size_t n); =20 #define __HAVE_ARCH_MEMSET16 @@ -55,7 +67,13 @@ static inline void *memset64(uint64_t *s, uint64_t v, si= ze_t n) } =20 #define __HAVE_ARCH_MEMMOVE +#if defined(__SANITIZE_MEMORY__) +#undef memmove +void *__msan_memmove(void *dest, const void *src, size_t len); +#define memmove __msan_memmove +#else void *memmove(void *dest, const void *src, size_t count); +#endif void *__memmove(void *dest, const void *src, size_t count); =20 int memcmp(const void *cs, const void *ct, size_t count); @@ -64,8 +82,7 @@ char *strcpy(char *dest, const char *src); char *strcat(char *dest, const char *src); int strcmp(const char *cs, const char *ct); =20 -#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__) - +#if (defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)) /* * For files that not instrumented (e.g. mm/slub.c) we * should use not instrumented version of mem* functions. @@ -73,7 +90,9 @@ int strcmp(const char *cs, const char *ct); =20 #undef memcpy #define memcpy(dst, src, len) __memcpy(dst, src, len) +#undef memmove #define memmove(dst, src, len) __memmove(dst, src, len) +#undef memset #define memset(s, c, n) __memset(s, c, n) =20 #ifndef __NO_FORTIFY diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h index a6cd6815f2490..b2c74cb85e20e 100644 --- a/include/linux/fortify-string.h +++ b/include/linux/fortify-string.h @@ -198,6 +198,7 @@ __FORTIFY_INLINE char *strncat(char *p, const char *q, = __kernel_size_t count) return p; } =20 +#ifndef CONFIG_KMSAN __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size) { size_t p_size =3D __builtin_object_size(p, 0); @@ -240,6 +241,7 @@ __FORTIFY_INLINE void *memmove(void *p, const void *q, = __kernel_size_t size) fortify_panic(__func__); return __underlying_memmove(p, q, size); } +#endif =20 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan= ); __FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size) --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF37EC433EF for ; Tue, 29 Mar 2022 12:54:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231252AbiC2M4i (ORCPT ); Tue, 29 Mar 2022 08:56:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49892 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236881AbiC2M4V (ORCPT ); Tue, 29 Mar 2022 08:56:21 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B7CE25D5C4 for ; Tue, 29 Mar 2022 05:42:28 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id l24-20020a056402231800b00410f19a3103so10968246eda.5 for ; Tue, 29 Mar 2022 05:42:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=GRTJFN5fI/eCQ6Ah2RQjb7/dqw7JAuAGzue9isPThnU=; b=V2A969r8azagnZbvbCjDak0q6MRkqtC8n5tFydFSoeWA+AZwbef6NPKlrrU+H+BRBM P6taNp8QY9FavRqmNYSwqrdYGQ97zsjJxhBcCNj+utxQuJ9nOPiopPtbBqzQ8gBr6Qzm 7SYENQDGsHWHESxdBNNfqefvYaEkKbqQ7Uw9rn3v77vq15hOdIJrJeEt188vunugqZcn Y6At8xC/ehmqb5IdQtbwYrfxqEDNNN28/KTOPS67Mp49F5QHDODlthVjEKpkMZlKaPm0 nF0jHasnFvBSUC3gLePFYURhT77L4PhtEKIV+vHO9KG0REyFSTNFBTme4w/CaQQAv4EV cm0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=GRTJFN5fI/eCQ6Ah2RQjb7/dqw7JAuAGzue9isPThnU=; b=2Nvvp7rYDszbH4950z+1sVbBB8kIN/zYzGPEc3J0UZWoXcPIVNJ2Aw2MQE689EwFyz 3dTByI+VphmHn6OIc3UPXZ3F7p5ZlitanCqCvtjTYrBGHghTBr4DOHqI97hIwuw9E/nf HEFNU9ptbxnzt4XToyuJbxRqPAvRAF5IiHRTyuJJuteJxLZuymeQF/m8zGKLjAywADsk xREO5tk+yJ1Sj7LDA5howaBtmeXnq0FbtiXORb+RSneeMbEKtZtyRtS86CmPdvdgrSpe RWuBYfT9yuhHkY1G5GdQ/UKYBIdOvkoESqwRVftGdeYltx824/nUpehsWU3GkiszvWFD 7KxA== X-Gm-Message-State: AOAM533alB4Ofa9Ffb4foT19RpaVVkuaBsoZ2H72B1tsS4TEQLUrOwe2 MaEXseVRxT1LEOAFqHn6Ufdv4IR9VxY= X-Google-Smtp-Source: ABdhPJzeBfVX40XVB+0DxQzCOfCbyY7YIWfJ+7MS3btbGbfEX8I9gsHnpMWWbEmqsPh4mt6QWJwzC2vkQok= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:c02:b0:6df:fb64:2770 with SMTP id ga2-20020a1709070c0200b006dffb642770mr34762165ejc.221.1648557746364; Tue, 29 Mar 2022 05:42:26 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:13 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-45-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 44/48] x86: kmsan: sync metadata pages on page fault From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KMSAN assumes shadow and origin pages for every allocated page are accessible. For pages between [VMALLOC_START, VMALLOC_END] those metadata pages start at KMSAN_VMALLOC_SHADOW_START and KMSAN_VMALLOC_ORIGIN_START, therefore we must sync a bigger memory region. Signed-off-by: Alexander Potapenko --- v2: -- addressed reports from kernel test robot Link: https://linux-review.googlesource.com/id/Ia5bd541e54f1ecc11b86666c3ec= 87c62ac0bdfb8 --- arch/x86/mm/fault.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index d0074c6ed31a3..f2250a32a10ca 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -260,7 +260,7 @@ static noinline int vmalloc_fault(unsigned long address) } NOKPROBE_SYMBOL(vmalloc_fault); =20 -void arch_sync_kernel_mappings(unsigned long start, unsigned long end) +static void __arch_sync_kernel_mappings(unsigned long start, unsigned long= end) { unsigned long addr; =20 @@ -284,6 +284,27 @@ void arch_sync_kernel_mappings(unsigned long start, un= signed long end) } } =20 +void arch_sync_kernel_mappings(unsigned long start, unsigned long end) +{ + __arch_sync_kernel_mappings(start, end); +#ifdef CONFIG_KMSAN + /* + * KMSAN maintains two additional metadata page mappings for the + * [VMALLOC_START, VMALLOC_END) range. These mappings start at + * KMSAN_VMALLOC_SHADOW_START and KMSAN_VMALLOC_ORIGIN_START and + * have to be synced together with the vmalloc memory mapping. + */ + if (start >=3D VMALLOC_START && end < VMALLOC_END) { + __arch_sync_kernel_mappings( + start - VMALLOC_START + KMSAN_VMALLOC_SHADOW_START, + end - VMALLOC_START + KMSAN_VMALLOC_SHADOW_START); + __arch_sync_kernel_mappings( + start - VMALLOC_START + KMSAN_VMALLOC_ORIGIN_START, + end - VMALLOC_START + KMSAN_VMALLOC_ORIGIN_START); + } +#endif +} + static bool low_pfn(unsigned long pfn) { return pfn < max_low_pfn; --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 88CCCC433F5 for ; Tue, 29 Mar 2022 12:49:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234809AbiC2MvR (ORCPT ); Tue, 29 Mar 2022 08:51:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53084 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236859AbiC2MsJ (ORCPT ); Tue, 29 Mar 2022 08:48:09 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 027EF25D5E9 for ; Tue, 29 Mar 2022 05:42:30 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id jl19-20020a17090775d300b006dff5abe965so8145895ejc.18 for ; Tue, 29 Mar 2022 05:42:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=RlYSbadXoEfpVHc0vV/XNEsRdhGi1prUW+giHTFauGk=; b=Dk6OfzDOhhWLYgl5XDrPV/wHbOcl0QIYza/6JtkZqHgLudavSZzmjMk+5f28h2orgU iHrCh6plBIwBN36pcmW+p7rGqqO0YMM7u/i5PR6jUmB+3M7Gvzrldrx36VWhdEly5wqL OCFVfyQ70Xqs++xgzaju3Y7LpDid5Y2SH/Q8CDmTucqxRIowd4s6C0QFAALHjEO+0nwB fuNr7hQPe/Epycuo17M1wj5VYq+p5MbKDJtrQQ5brwghYeQJKrjFvhP1FeN553lIB4Ty /plVPtHNwRzPgAYEUGGThxWuO/QztfBN6vGOWx0oeHAc0cwrK2ZfAWzl7GaTEqAJcx59 JBIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=RlYSbadXoEfpVHc0vV/XNEsRdhGi1prUW+giHTFauGk=; b=SVFkT/0nrRcA3791RiCxiAKIlybD6K9V4CAxgnJnRcMdUptdpCElY9CWkwIRc3kS18 4or6J9J5r6SK3MRopy3EW01NKi25HHApKK6ZwHh9LDZtcjlOy0PDO03eFcyIcjdKSaru GcliQOCHCgBY1dmIuavDvdTLZnMntMGeP0DHT83Ks9VOmJZjnOoc8P4iSVNNh2K/rvy4 bNd1gylMTd4Zk30zX7gLq/BVNCnF3WIuaSYnPE7i1e8NgDzlnYOf5QDdy95dKw/jQg4q IENEoGbzdMyC0LCsPn2fke3NG86ligkzytGZj+lwDb25fLnQVVDIWj3UNPRrnyhHNzD9 v9KQ== X-Gm-Message-State: AOAM532pBfEMMFYbaq7fycu7PTc1LVi0yZRaebU75ukgFhJxGZ3Vjvzd +deq9FWB3YJI81lpQNGeMcYCQ8PQ7oM= X-Google-Smtp-Source: ABdhPJwAQ2KpkKZtt/s3LazFEoxsBevCE6SqXEdguMxH7F8FiFrFs/1K5CRo60urh/1AvLKrhdVF+1gfvd0= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:907:2d20:b0:6df:8c3f:730a with SMTP id gs32-20020a1709072d2000b006df8c3f730amr34340038ejc.725.1648557748867; Tue, 29 Mar 2022 05:42:28 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:14 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-46-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 45/48] x86: kasan: kmsan: support CONFIG_GENERIC_CSUM on x86, enable it for KASAN/KMSAN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This is needed to allow memory tools like KASAN and KMSAN see the memory accesses from the checksum code. Without CONFIG_GENERIC_CSUM the tools can't see memory accesses originating from handwritten assembly code. For KASAN it's a question of detecting more bugs, for KMSAN using the C implementation also helps avoid false positives originating from seemingly uninitialized checksum values. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I3e95247be55b1112af59dbba07e= 8cbf34e50a581 --- arch/x86/Kconfig | 4 ++++ arch/x86/include/asm/checksum.h | 16 ++++++++++------ arch/x86/lib/Makefile | 2 ++ 3 files changed, 16 insertions(+), 6 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 9f5bd41bf660c..86df15017f79d 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -315,6 +315,10 @@ config GENERIC_ISA_DMA def_bool y depends on ISA_DMA_API =20 +config GENERIC_CSUM + bool + default y if KMSAN || KASAN + config GENERIC_BUG def_bool y depends on BUG diff --git a/arch/x86/include/asm/checksum.h b/arch/x86/include/asm/checksu= m.h index bca625a60186c..6df6ece8a28ec 100644 --- a/arch/x86/include/asm/checksum.h +++ b/arch/x86/include/asm/checksum.h @@ -1,9 +1,13 @@ /* SPDX-License-Identifier: GPL-2.0 */ -#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 1 -#define HAVE_CSUM_COPY_USER -#define _HAVE_ARCH_CSUM_AND_COPY -#ifdef CONFIG_X86_32 -# include +#ifdef CONFIG_GENERIC_CSUM +# include #else -# include +# define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 1 +# define HAVE_CSUM_COPY_USER +# define _HAVE_ARCH_CSUM_AND_COPY +# ifdef CONFIG_X86_32 +# include +# else +# include +# endif #endif diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index f76747862bd2e..7ba5f61d72735 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -65,7 +65,9 @@ ifneq ($(CONFIG_X86_CMPXCHG64),y) endif else obj-y +=3D iomap_copy_64.o +ifneq ($(CONFIG_GENERIC_CSUM),y) lib-y +=3D csum-partial_64.o csum-copy_64.o csum-wrappers_64.o +endif lib-y +=3D clear_page_64.o copy_page_64.o lib-y +=3D memmove_64.o memset_64.o lib-y +=3D copy_user_64.o --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 249C1C433EF for ; Tue, 29 Mar 2022 12:55:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237059AbiC2M4u (ORCPT ); Tue, 29 Mar 2022 08:56:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48508 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236944AbiC2M42 (ORCPT ); Tue, 29 Mar 2022 08:56:28 -0400 Received: from mail-ed1-x54a.google.com (mail-ed1-x54a.google.com [IPv6:2a00:1450:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 637A325D5F6 for ; Tue, 29 Mar 2022 05:42:33 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id i4-20020aa7c9c4000000b00419c542270dso5231460edt.8 for ; Tue, 29 Mar 2022 05:42:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=0QWUQ+RqE8jiHyj7/O+KujG6tRpsbOFA8yuMseJPgVs=; b=OfXq72ZoBUQGSWSvm4KVtJ07Y6J70d5V6dAjwsYPNQ8KvQs+UemAzoD9b+EXKX/OTw Q+izHPhM0oLIkOLIiuKDw0qaaM3HmxBX8q8lxNCUTVCL6uMVfLhs0yBqTwJyZYo3a2Dd PHMlh5zEbtKHkaJRb6sAKEdQbGhEcA7fqUGVsUSQYvLsCZPqYBZ6kCgNZI+IIO0DTiYw dKXtVOTB8fspK7u9aonJCNi788zBxPM+etWoLtYNpYHL5mhBEusrVsXgVIm9RsvEQvVL BVUcgD1GuztoqNHxl+h1HcQQt1n0AN97ckOSFFHrUUEbkVxi2NvTa3+e0HN0zz3+BFfO qT4Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=0QWUQ+RqE8jiHyj7/O+KujG6tRpsbOFA8yuMseJPgVs=; b=PDY8fE3Gusc6lWa+pyPyVK416v8WtkkZpciIudAZD7xrzcdgjMBDb/6nfolfzvqUNU BQBOhWVFiwKqb5kLcUzs9k3nI2N0TULxZqxKIOgtfaRX424BROz4PzRwbr3aR6zoA4Vn 66rEmElzzfYOvaJ9Fzy/laDyQBo6rUmS5zbWPoUO4OVfhE5LovfsyH4QM+DR6b/ZQIqd Ms3XBbRcFlkgqx7Y5Hqg95H76VoLsxBXkCyUISJRwGthcweKDX/lLnKyQ/0XXcK29WNx kvpnhqoI4Wdkul52Vz5yfgXTt8ej11nry3EPDQ498RWfuqZnPaJYOTLqFq5G8ss9RN6c HYoQ== X-Gm-Message-State: AOAM530UlQ2ueWHWsAOct2mDLtkOGZAXR7EL9LtMaxbFebDT9dWdp860 sUSU0viYEckvn7bh0M7qLHnvxbID0g4= X-Google-Smtp-Source: ABdhPJytokWuo6v19GSWg2KLHdtKqtVYC2QIF6Shk0LT4bep8x7ZGLJY2F5r9sIe9kWDKcupdjioDqnZsL8= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:948:b0:6d6:e479:1fe4 with SMTP id j8-20020a170906094800b006d6e4791fe4mr33417649ejd.240.1648557751382; Tue, 29 Mar 2022 05:42:31 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:15 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-47-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 46/48] x86: fs: kmsan: disable CONFIG_DCACHE_WORD_ACCESS From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Andrey Konovalov Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" dentry_string_cmp() calls read_word_at_a_time(), which might read uninitialized bytes to optimize string comparisons. Disabling CONFIG_DCACHE_WORD_ACCESS should prohibit this optimization, as well as (probably) similar ones. Suggested-by: Andrey Konovalov Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I4c0073224ac2897cafb8c037362= c49dda9cfa133 --- arch/x86/Kconfig | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 86df15017f79d..646a7849be4cf 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -126,7 +126,9 @@ config X86 select CLKEVT_I8253 select CLOCKSOURCE_VALIDATE_LAST_CYCLE select CLOCKSOURCE_WATCHDOG - select DCACHE_WORD_ACCESS + # Word-size accesses may read uninitialized data past the trailing \0 + # in strings and cause false KMSAN reports. + select DCACHE_WORD_ACCESS if !KMSAN select DYNAMIC_SIGFRAME select EDAC_ATOMIC_SCRUB select EDAC_SUPPORT --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53B3CC4332F for ; Tue, 29 Mar 2022 12:55:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237051AbiC2M4s (ORCPT ); Tue, 29 Mar 2022 08:56:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236364AbiC2M4Y (ORCPT ); Tue, 29 Mar 2022 08:56:24 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4805825DAAF for ; Tue, 29 Mar 2022 05:42:38 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id o20-20020aa7dd54000000b00413bc19ad08so10970322edw.7 for ; Tue, 29 Mar 2022 05:42:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=SXzoEK+WJk4pacaOPaL1kxqndb2ET/uQVttgxEkML+w=; b=EBgX4Z2SSMT4cCzIkiyvRhgKVrX4GCoNERzYeL3X7WwtwGGVnYOFgUHYNinxWjvjqh kPkONHRo3AKKxZf7R9b/cbfY+0RkKOgrN2sHOaZlXcyZw9J83ocbcq3eROphMcFU1OEF YKJAZFiUIL4gSt2ikNRjoKRlkYyZREXJJz7VZhoC8/sgm/33yNzmvyYsBx61nm/5RFi7 Uan2pjppFHg5+0ZzLB/M100362XN/KNKnBk+E1pryuHawtyJIDPxaGso4I1pLwK0vTOC Sf0uIg6BZNx/aUM8AwFe9jVH9IO3gu9QyjACglxQsPj/loJje/iBcBYgMBagUP0EX/7M jrPw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=SXzoEK+WJk4pacaOPaL1kxqndb2ET/uQVttgxEkML+w=; b=HNL3veLcrpHDEvPj4Gr7m0oihcoxrRIlvGO232kS0YGD0KznhnEvXfyFv2m1TYTCZ7 LN9cHcwh2NYdMlMV2enypf7CEBWeTYiX6OqHO4euoSWsBLvWhZkiPY1U4M7CbCoPi4Dv 1NVMPGVBIOKM8KMKqxKlukh4Iaddx4h/hLamkclQDHhTbqBtBg8GN6jymxFw/VeJjdox /1414JOZL4USS3r5FgbJtIZiMDZa3cLoiPxh+DspANl6zbRE5JRJuj/CapIN4WrXmCjV wLyE3D860fCEHbZusNZE6UGAJeboEexvuKbjk+KYDANlSgM5QdUbQZE10zQUVbBmpAgK lkKQ== X-Gm-Message-State: AOAM530Su4G30LfnjpM8/fXRu7NHSvU6pkLfnl8oAkK8u5BkQ3bZ4FEN 4f7vZIsg+h8b26Moeiy6vWEos52GYGY= X-Google-Smtp-Source: ABdhPJy8fACfQ4jyGr9xF342/z75NoNcLTDY10G+LWoaiStO0hTLZbGlHwL73c3ZjRYtS31XbeKhwJgw3p0= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:9acd:b0:6e0:b74d:d932 with SMTP id ah13-20020a1709069acd00b006e0b74dd932mr24156373ejc.695.1648557754011; Tue, 29 Mar 2022 05:42:34 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:16 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-48-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 47/48] x86: kmsan: handle register passing from uninstrumented code From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Replace instrumentation_begin() with instrumentation_begin_with_regs() to let KMSAN handle the non-instrumented code and unpoison pt_regs passed from the instrumented part. This is done to reduce the number of false positive reports. Signed-off-by: Alexander Potapenko --- v2: -- this patch was previously called "x86: kmsan: handle register passing from uninstrumented code". Instead of adding KMSAN-specific code to every instrumentation_begin()/instrumentation_end() section, we changed instrumentation_begin() to instrumentation_begin_with_regs() where applicable. Link: https://linux-review.googlesource.com/id/I435ec076cd21752c2f877f5da81= f5eced62a2ea4 --- arch/x86/entry/common.c | 3 ++- arch/x86/include/asm/idtentry.h | 10 +++++----- arch/x86/kernel/cpu/mce/core.c | 2 +- arch/x86/kernel/kvm.c | 2 +- arch/x86/kernel/nmi.c | 2 +- arch/x86/kernel/sev.c | 4 ++-- arch/x86/kernel/traps.c | 14 +++++++------- arch/x86/mm/fault.c | 2 +- 8 files changed, 20 insertions(+), 19 deletions(-) diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 6c2826417b337..047d157987859 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -75,7 +76,7 @@ __visible noinstr void do_syscall_64(struct pt_regs *regs= , int nr) add_random_kstack_offset(); nr =3D syscall_enter_from_user_mode(regs, nr); =20 - instrumentation_begin(); + instrumentation_begin_with_regs(regs); =20 if (!do_syscall_x64(regs, nr) && !do_syscall_x32(regs, nr) && nr !=3D -1)= { /* Invalid system call, but still a system call. */ diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentr= y.h index 1345088e99025..f24ff33fc3681 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -51,7 +51,7 @@ __visible noinstr void func(struct pt_regs *regs) \ { \ irqentry_state_t state =3D irqentry_enter(regs); \ \ - instrumentation_begin(); \ + instrumentation_begin_with_regs(regs); \ __##func (regs); \ instrumentation_end(); \ irqentry_exit(regs, state); \ @@ -98,7 +98,7 @@ __visible noinstr void func(struct pt_regs *regs, \ { \ irqentry_state_t state =3D irqentry_enter(regs); \ \ - instrumentation_begin(); \ + instrumentation_begin_with_regs(regs); \ __##func (regs, error_code); \ instrumentation_end(); \ irqentry_exit(regs, state); \ @@ -195,7 +195,7 @@ __visible noinstr void func(struct pt_regs *regs, \ irqentry_state_t state =3D irqentry_enter(regs); \ u32 vector =3D (u32)(u8)error_code; \ \ - instrumentation_begin(); \ + instrumentation_begin_with_regs(regs); \ kvm_set_cpu_l1tf_flush_l1d(); \ run_irq_on_irqstack_cond(__##func, regs, vector); \ instrumentation_end(); \ @@ -235,7 +235,7 @@ __visible noinstr void func(struct pt_regs *regs) \ { \ irqentry_state_t state =3D irqentry_enter(regs); \ \ - instrumentation_begin(); \ + instrumentation_begin_with_regs(regs); \ kvm_set_cpu_l1tf_flush_l1d(); \ run_sysvec_on_irqstack_cond(__##func, regs); \ instrumentation_end(); \ @@ -262,7 +262,7 @@ __visible noinstr void func(struct pt_regs *regs) \ { \ irqentry_state_t state =3D irqentry_enter(regs); \ \ - instrumentation_begin(); \ + instrumentation_begin_with_regs(regs); \ __irq_enter_raw(); \ kvm_set_cpu_l1tf_flush_l1d(); \ __##func (regs); \ diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 5818b837fd4d4..7b8c43d8727cc 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -1355,7 +1355,7 @@ static void queue_task_work(struct mce *m, char *msg,= void (*func)(struct callba /* Handle unconfigured int18 (should never happen) */ static noinstr void unexpected_machine_check(struct pt_regs *regs) { - instrumentation_begin(); + instrumentation_begin_with_regs(regs); pr_err("CPU#%d: Unexpected int18 (Machine Check)\n", smp_processor_id()); instrumentation_end(); diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index d77481ecb0d5f..eaed9b412908c 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -249,7 +249,7 @@ noinstr bool __kvm_handle_async_pf(struct pt_regs *regs= , u32 token) return false; =20 state =3D irqentry_enter(regs); - instrumentation_begin(); + instrumentation_begin_with_regs(regs); =20 /* * If the host managed to inject an async #PF into an interrupt diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 4bce802d25fb1..3f987a5dc38c7 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -329,7 +329,7 @@ static noinstr void default_do_nmi(struct pt_regs *regs) =20 __this_cpu_write(last_nmi_rip, regs->ip); =20 - instrumentation_begin(); + instrumentation_begin_with_regs(regs); =20 handled =3D nmi_handle(NMI_LOCAL, regs); __this_cpu_add(nmi_stats.normal, handled); diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index e6d316a01fdd4..9bfc29fc9c983 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -1330,7 +1330,7 @@ DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication) =20 irq_state =3D irqentry_nmi_enter(regs); =20 - instrumentation_begin(); + instrumentation_begin_with_regs(regs); =20 if (!vc_raw_handle_exception(regs, error_code)) { /* Show some debug info */ @@ -1362,7 +1362,7 @@ DEFINE_IDTENTRY_VC_USER(exc_vmm_communication) } =20 irqentry_enter_from_user_mode(regs); - instrumentation_begin(); + instrumentation_begin_with_regs(regs); =20 if (!vc_raw_handle_exception(regs, error_code)) { /* diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 8143693a7ea6e..f08741abc0e5b 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -229,7 +229,7 @@ static noinstr bool handle_bug(struct pt_regs *regs) /* * All lies, just get the WARN/BUG out. */ - instrumentation_begin(); + instrumentation_begin_with_regs(regs); /* * Since we're emulating a CALL with exceptions, restore the interrupt * state to what it was at the exception site. @@ -260,7 +260,7 @@ DEFINE_IDTENTRY_RAW(exc_invalid_op) return; =20 state =3D irqentry_enter(regs); - instrumentation_begin(); + instrumentation_begin_with_regs(regs); handle_invalid_op(regs); instrumentation_end(); irqentry_exit(regs, state); @@ -414,7 +414,7 @@ DEFINE_IDTENTRY_DF(exc_double_fault) #endif =20 irqentry_nmi_enter(regs); - instrumentation_begin(); + instrumentation_begin_with_regs(regs); notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV); =20 tsk->thread.error_code =3D error_code; @@ -690,14 +690,14 @@ DEFINE_IDTENTRY_RAW(exc_int3) */ if (user_mode(regs)) { irqentry_enter_from_user_mode(regs); - instrumentation_begin(); + instrumentation_begin_with_regs(regs); do_int3_user(regs); instrumentation_end(); irqentry_exit_to_user_mode(regs); } else { irqentry_state_t irq_state =3D irqentry_nmi_enter(regs); =20 - instrumentation_begin(); + instrumentation_begin_with_regs(regs); if (!do_int3(regs)) die("int3", regs, 0); instrumentation_end(); @@ -896,7 +896,7 @@ static __always_inline void exc_debug_kernel(struct pt_= regs *regs, */ unsigned long dr7 =3D local_db_save(); irqentry_state_t irq_state =3D irqentry_nmi_enter(regs); - instrumentation_begin(); + instrumentation_begin_with_regs(regs); =20 /* * If something gets miswired and we end up here for a user mode @@ -975,7 +975,7 @@ static __always_inline void exc_debug_user(struct pt_re= gs *regs, */ =20 irqentry_enter_from_user_mode(regs); - instrumentation_begin(); + instrumentation_begin_with_regs(regs); =20 /* * Start the virtual/ptrace DR6 value with just the DR_STEP mask diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index f2250a32a10ca..676e394f1af5b 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1557,7 +1557,7 @@ DEFINE_IDTENTRY_RAW_ERRORCODE(exc_page_fault) */ state =3D irqentry_enter(regs); =20 - instrumentation_begin(); + instrumentation_begin_with_regs(regs); handle_page_fault(regs, error_code, address); instrumentation_end(); =20 --=20 2.35.1.1021.g381101b075-goog From nobody Sun Jun 21 10:06:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 176E0C433F5 for ; Tue, 29 Mar 2022 12:48:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236659AbiC2MuF (ORCPT ); Tue, 29 Mar 2022 08:50:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236932AbiC2MsO (ORCPT ); Tue, 29 Mar 2022 08:48:14 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B58D725F641 for ; Tue, 29 Mar 2022 05:42:47 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id v9-20020a509549000000b00418d7c2f62aso10949038eda.15 for ; Tue, 29 Mar 2022 05:42:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=BxrNv7I9TyEaPnGly7TdSY5yHzK/Q3Z4xNLrOUnkClQ=; b=F1YYot40OfwHFlJIBEjvvi7+vEf+sISqzpxyEMm9RXg7yBeYOovpz1ifEVjxkb+8Tp ug846iZxjLR7LfZGindUZ5W5ZYWx9SXUM/LIzPff3L9xOwWnmqR34pPLPPicL7EpVaWh BceAVU1QYjQ33h5UnMxF7NMbTCP79zz+hCjBe7DzaqQKiuOmpo0Q92dqE8k4H4xhYPJ5 8QBDPgbSjW2Dxw8rRJh4j124haAPk3WZ7kH3MZRK7aTRX+53Kfdw+whZ5Qh3OkEuEe4V /YzlCDf1dkIQcIX6qS1kNTRw9/AS3wlsNX6fJ044mUGy/rWkdQ4G5sXgY/2nnNeFCaLN ovQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=BxrNv7I9TyEaPnGly7TdSY5yHzK/Q3Z4xNLrOUnkClQ=; b=pChCIOBw5Gwsp1UMHjnMYttdpjWi9Cd7wkYMPALOGWCmPqopcg0GHkwz7JDTCExlbV f+Zzo8PLhpMOm8CabCEPiu0yD3Ef83VdIYlbZGgRrHZkEm4zcB8KMVbsfERL62ptJRiq A5zMTYTTeq2aDAP/04dG9avWOe0jrrrJjfc5pwPq6ntQUYmMHuGCsZ0CS7CHvOdf6D3J qcG+Ho5N5BlzOOisbK430wc/rfPT5o6uWmz+fuBAs8SPgcAh1a4QdffvAuFrp4WMa7Nw VGqi0JxwW049Y08lYUGsuBcciImbaBGzZ0JaGAZWMzdUxolqPwGlMVoCEizopH7AOd2S nGrw== X-Gm-Message-State: AOAM53338x+PGjQHcIY04VdZvTjtHN7Vk4hRBL8w4xeDdTVw6bPbil7w HNaY0vEDWS210tBcOj+k4OmQhe5ncgU= X-Google-Smtp-Source: ABdhPJwCpxSBAahtijoWXTLXmqk0cIsPTNznjrswrMwUWM6rymRvh0IEM+UvEt2qc+MfcoyqAjf1DJp1rgo= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:c1c6:b0:6d5:cc27:a66c with SMTP id bw6-20020a170906c1c600b006d5cc27a66cmr35151648ejb.650.1648557756848; Tue, 29 Mar 2022 05:42:36 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:17 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-49-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 48/48] x86: kmsan: enable KMSAN builds for x86 From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Make KMSAN usable by adding the necessary Kconfig bits. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I1d295ce8159ce15faa496d20089= d953a919c125e --- arch/x86/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 646a7849be4cf..1c4601e198d5c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -165,6 +165,7 @@ config X86 select HAVE_ARCH_KASAN if X86_64 select HAVE_ARCH_KASAN_VMALLOC if X86_64 select HAVE_ARCH_KFENCE + select HAVE_ARCH_KMSAN if X86_64 select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT --=20 2.35.1.1021.g381101b075-goog