From nobody Tue Apr 7 14:52:31 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 06049ECAAD4 for ; Fri, 26 Aug 2022 15:08:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243776AbiHZPIY (ORCPT ); Fri, 26 Aug 2022 11:08:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33420 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240737AbiHZPIS (ORCPT ); Fri, 26 Aug 2022 11:08:18 -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 6FB6ADB7F4 for ; Fri, 26 Aug 2022 08:08:17 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id w20-20020a05640234d400b00447e6ffefccso1263574edc.0 for ; Fri, 26 Aug 2022 08:08:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=J3VjO5owb76kN3paB0OLHywjIHrYCcgYmjupWIyAPgw=; b=aCsHGgV2sJxTYt+AJn+GIymUxqtSkf7JOSyz7vtwxv7vS0L3uEaVpG7DpI3UZFn7Rf D7zIWrIK46DZU/rRMq3m92P1QW307EPb+BIJOkzmXqQ8PCl2pATj4E2Z1WkltcOGRGH6 X4s+ctoBmXCp+cOHvURIAa7E0w3KL/dAIMuJ3L8QZdm/NfQUl1dcR/AaILFXFY/SbQCL 36XR8pcZkoIw/0JS2OLp31Xw05XYV+OvrpL2omMECtGFmMj4DIIeOo98maVmQrFF8Xkl zgX7H+3jSLRXR+rJBrs8fyG/5arariUD9UxBlfK0i9oPhMg0ntqpE7GJ0QJEkhQTjoVw jDPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=J3VjO5owb76kN3paB0OLHywjIHrYCcgYmjupWIyAPgw=; b=6CeqeICw8tF1lXDAvi6uUJoN03oQnOx/B55FgSXDJ8knFW2ojsYPNvJQRrsw5gvawi KkhJa1DNoXhcp/5vErtRvYiAUaYhis3EkoqI14DGJEslJ+poVD/iV1eOlrlt2gWNLtO+ CNthm2j5F8CXLbZ9UeU4mRPggUJ0UBmHEM1wfreUZMJ7VuLKJDsiwFtT6nhA3zz+tDew 8CmpqcE3MnSLThNZmmNTEgpAdiuJvxBj47OHiq2RuPIrS9yHetSINGtoFnOEM50SI9Mx cL+YQspTPtKTJ1ni1DxpfxaDHBjzSbB/KSs6UcxKH9OpUS2BdRKz/Dpwod0lGSOOaSDB hCcg== X-Gm-Message-State: ACgBeo1/BXriY/TdedaPbFB2B/X0N7pn6Y9fU0JhhcKIg1BcqsGWgSLP yeQfGmKEmkbCIq+KU3L0FqLuT/GMUeM= X-Google-Smtp-Source: AA6agR6nNKRDoPy16VFGdamdWo+M+pvpnHCU2sYnAni0z8NRtgZc0jeuf/gSF+/K7FUxMeTnWWm/3XJf1sI= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:aa7:c611:0:b0:447:844d:e5a2 with SMTP id h17-20020aa7c611000000b00447844de5a2mr7350187edq.10.1661526495846; Fri, 26 Aug 2022 08:08:15 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:24 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-2-glider@google.com> Subject: [PATCH v5 01/44] x86: add missing include to sparsemem.h From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 Including sparsemem.h from other files (e.g. transitively via asm/pgtable_64_types.h) results in compilation errors due to unknown types: 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); ^ Fix these errors by including linux/types.h from sparsemem.h This is required for the upcoming KMSAN patches. 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 1E1D3ECAAA3 for ; Fri, 26 Aug 2022 15:08:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243882AbiHZPIp (ORCPT ); Fri, 26 Aug 2022 11:08:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240737AbiHZPIh (ORCPT ); Fri, 26 Aug 2022 11:08:37 -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 8EEACDC09D for ; Fri, 26 Aug 2022 08:08:20 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id qf15-20020a1709077f0f00b0073d6dfb7556so717119ejc.12 for ; Fri, 26 Aug 2022 08:08:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=omcyQ1o+RVSxzRVZJZY/qms7uBp4WMcvPZ8eVf62Bcs=; b=RA3+jZoNkZ6/iwxrpSVqaEjBMYHmdlwKi/r0P/ahW5EfxcEw95Fn/Idn7YL4qWBzll SY0uIX1NPhBlO4/v7JGD0C0GkUj5lA5653SGiEmNx4TDtgxGUvAKdSJ1fWOgyi06z/DG shPVR/vk4/TLqx/3mkmush3fs6dqtOR0yJmc+Nmy6aUkZqpT99d7lDvu0GcomBqNMqyN 19J1+veiw9TqSFJT2q2s9xkLUwnPBJrzd2UWFkMwuPWi4IOaRL2IjhrBf3Js6HDjqwHq CmvYYiW1TiqGPg7RFvpwRKn+givLPrkzFJ3DaBqEgQYzQViRUdbgNutzUbpd5CLnFdln k03w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=omcyQ1o+RVSxzRVZJZY/qms7uBp4WMcvPZ8eVf62Bcs=; b=t8jL5AQxGFyoBnCeebfNnTmZAi6Y5vWOFakGSUQFU9arbOprosLh1XzZjHcOTim7yu BupCBXbrM+Q+IhBK1gKY4qKChTNMl3SCF884fJPFNBfK6AISrzZdCjjr0aKMWj+SRKiY sXzeOafNN36c4e/uR7BkZF5IaNJWuMaJebD6ub9I6LjAzIZDoTwYbPF3ewddV0sBwv/g WBmkXhgwxS9ZWyUeY9jDEvF/l5usIlQhFLfOYCLXbTTCRz5P/uyuF8UyiVF/xT7qT2j4 tJTumtmOa2x0k0NH7Pz74Xm4VAE22ZCMnDsopnqug3Jr4RQPUfgqV7Q/ssOp1ceEJtIs M5hg== X-Gm-Message-State: ACgBeo0+R/9NovLXJpromJKnGXUISrWR/Tx4KDYNWTzjOxGw0iwZ01jW 7oSP90vqitkDTFza3vuTNGeF1ZYmwMQ= X-Google-Smtp-Source: AA6agR6A/llRpE6oXEfhGAAL2j75O1MUVXyWFGmAFUP5rzL7sdADsGx3VSQrZnp9gBHmtwE7SwLSgksGbo8= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:270a:b0:446:c9e9:6e00 with SMTP id y10-20020a056402270a00b00446c9e96e00mr6913543edd.315.1661526498732; Fri, 26 Aug 2022 08:08:18 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:25 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-3-glider@google.com> Subject: [PATCH v5 02/44] stackdepot: reserve 5 extra bits in depot_stack_handle_t From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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. Also adapt KASAN to the new prototype by passing extra_bits=3D0, as KASAN does not intend to store additional information in the stack handle. Signed-off-by: Alexander Potapenko Reviewed-by: Marco Elver --- v4: -- per Marco Elver's request, fold "kasan: common: adapt to the new prototype of __stack_depot_save()" into this patch to prevent bisection breakages. Link: https://linux-review.googlesource.com/id/I0587f6c777667864768daf07821= d594bce6d8ff9 --- include/linux/stackdepot.h | 8 ++++++++ lib/stackdepot.c | 29 ++++++++++++++++++++++++----- mm/kasan/common.c | 2 +- 3 files changed, 33 insertions(+), 6 deletions(-) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index bc2797955de90..9ca7798d7a318 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 /* @@ -59,6 +65,8 @@ 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 e73fda23388d8..79e894cf84064 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -43,7 +43,8 @@ #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) ? \ @@ -56,6 +57,7 @@ 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 @@ -77,6 +79,14 @@ 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) @@ -140,6 +150,7 @@ 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 @@ -382,6 +393,7 @@ 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) * @@ -393,6 +405,10 @@ 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 @@ -402,10 +418,11 @@ 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; @@ -489,9 +506,11 @@ 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 @@ -511,6 +530,6 @@ 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); diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 69f583855c8be..94caa2d46a327 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 E5021ECAAA3 for ; Fri, 26 Aug 2022 15:08:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244204AbiHZPIv (ORCPT ); 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Fri, 26 Aug 2022 08:08:21 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:26 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-4-glider@google.com> Subject: [PATCH v5 03/44] instrumented.h: allow instrumenting both sides of copy_from_user() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 Reviewed-by: Marco Elver --- v4: -- fix _copy_from_user_key() in arch/s390/lib/uaccess.c (Reported-by: kernel test robot ) Link: https://linux-review.googlesource.com/id/I855034578f0b0f126734cbd734f= b4ae1d3a6af99 --- arch/s390/lib/uaccess.c | 3 ++- include/linux/instrumented.h | 21 +++++++++++++++++++-- include/linux/uaccess.h | 19 ++++++++++++++----- lib/iov_iter.c | 9 ++++++--- lib/usercopy.c | 3 ++- 5 files changed, 43 insertions(+), 12 deletions(-) diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c index d7b3b193d1088..58033dfcb6d45 100644 --- a/arch/s390/lib/uaccess.c +++ b/arch/s390/lib/uaccess.c @@ -81,8 +81,9 @@ unsigned long _copy_from_user_key(void *to, const void __= user *from, =20 might_fault(); if (!should_fail_usercopy()) { - instrument_copy_from_user(to, from, n); + instrument_copy_from_user_before(to, from, n); res =3D raw_copy_from_user_key(to, from, n, key); + instrument_copy_from_user_after(to, from, n, res); } if (unlikely(res)) memset(to + (n - res), 0, res); 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 47e5d374c7ebe..afb18f198843b 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -58,20 +58,28 @@ 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 /** @@ -115,8 +123,9 @@ _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 4b7fce72e3e52..c3ca28ca68a65 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -174,13 +174,16 @@ 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 inline struct pipe_buffer *pipe_buf(const struct pipe_inode_info *p= ipe, 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 B3AF8ECAAA3 for ; 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Fri, 26 Aug 2022 08:08:24 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:27 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-5-glider@google.com> Subject: [PATCH v5 04/44] x86: asm: instrument usercopy in get_user() and put_user() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 variations of get_user() and put_user(). Signed-off-by: Alexander Potapenko --- v5: -- handle put_user(), make sure to not evaluate pointer/value twice Link: https://linux-review.googlesource.com/id/Ia9f12bfe5832623250e20f1859f= df5cc485a2fce --- arch/x86/include/asm/uaccess.h | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 913e593a3b45f..c1b8982899eca 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 @@ -103,6 +104,7 @@ extern int __get_user_bad(void); : "=3Da" (__ret_gu), "=3Dr" (__val_gu), \ ASM_CALL_CONSTRAINT \ : "0" (ptr), "i" (sizeof(*(ptr)))); \ + instrument_get_user(__val_gu); \ (x) =3D (__force __typeof__(*(ptr))) __val_gu; \ __builtin_expect(__ret_gu, 0); \ }) @@ -192,9 +194,11 @@ extern void __put_user_nocheck_8(void); int __ret_pu; \ void __user *__ptr_pu; \ register __typeof__(*(ptr)) __val_pu asm("%"_ASM_AX); \ - __chk_user_ptr(ptr); \ - __ptr_pu =3D (ptr); \ - __val_pu =3D (x); \ + __typeof__(*(ptr)) __x =3D (x); /* eval x once */ \ + __typeof__(ptr) __ptr =3D (ptr); /* eval ptr once */ \ + __chk_user_ptr(__ptr); \ + __ptr_pu =3D __ptr; \ + __val_pu =3D __x; \ asm volatile("call __" #fn "_%P[size]" \ : "=3Dc" (__ret_pu), \ ASM_CALL_CONSTRAINT \ @@ -202,6 +206,7 @@ extern void __put_user_nocheck_8(void); "r" (__val_pu), \ [size] "i" (sizeof(*(ptr))) \ :"ebx"); \ + instrument_put_user(__x, __ptr, sizeof(*(ptr))); \ __builtin_expect(__ret_pu, 0); \ }) =20 @@ -248,23 +253,25 @@ extern void __put_user_nocheck_8(void); =20 #define __put_user_size(x, ptr, size, label) \ do { \ + __typeof__(*(ptr)) __x =3D (x); /* eval x once */ \ __chk_user_ptr(ptr); \ switch (size) { \ case 1: \ - __put_user_goto(x, ptr, "b", "iq", label); \ + __put_user_goto(__x, ptr, "b", "iq", label); \ break; \ case 2: \ - __put_user_goto(x, ptr, "w", "ir", label); \ + __put_user_goto(__x, ptr, "w", "ir", label); \ break; \ case 4: \ - __put_user_goto(x, ptr, "l", "ir", label); \ + __put_user_goto(__x, ptr, "l", "ir", label); \ break; \ case 8: \ - __put_user_goto_u64(x, ptr, label); \ + __put_user_goto_u64(__x, ptr, label); \ break; \ default: \ __put_user_bad(); \ } \ + instrument_put_user(__x, ptr, size); \ } while (0) =20 #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT @@ -305,6 +312,7 @@ do { \ default: \ (x) =3D __get_user_bad(); \ } \ + instrument_get_user(x); \ } while (0) =20 #define __get_user_asm(x, addr, itype, ltype, label) \ --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 B61F8ECAAD5 for ; Fri, 26 Aug 2022 15:09:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231171AbiHZPJY (ORCPT ); Fri, 26 Aug 2022 11:09:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33958 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244087AbiHZPIk (ORCPT ); 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Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , kasan-dev@googlegroups.com, 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 Reviewed-by: Marco Elver --- v5: -- cast user pointers to `void __user *` Link: https://linux-review.googlesource.com/id/Ic1ee8da1886325f46ad67f52176= f48c2c836c48f --- include/asm-generic/cacheflush.h | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/include/asm-generic/cacheflush.h b/include/asm-generic/cachefl= ush.h index 4f07afacbc239..f46258d1a080f 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; @@ -105,14 +107,22 @@ static inline void flush_cache_vunmap(unsigned long s= tart, unsigned long end) #ifndef copy_to_user_page #define copy_to_user_page(vma, page, vaddr, dst, src, len) \ do { \ + instrument_copy_to_user((void __user *)dst, src, len); \ memcpy(dst, src, len); \ flush_icache_user_page(vma, page, vaddr, len); \ } while (0) #endif =20 + #ifndef copy_from_user_page -#define copy_from_user_page(vma, page, vaddr, dst, src, len) \ - memcpy(dst, src, len) +#define copy_from_user_page(vma, page, vaddr, dst, src, len) \ + do { \ + instrument_copy_from_user_before(dst, (void __user *)src, \ + len); \ + memcpy(dst, src, len); \ + instrument_copy_from_user_after(dst, (void __user *)src, len, \ + 0); \ + } while (0) #endif =20 #endif /* _ASM_GENERIC_CACHEFLUSH_H */ --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 57BA5ECAAD6 for ; Fri, 26 Aug 2022 15:09:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245061AbiHZPJ3 (ORCPT ); Fri, 26 Aug 2022 11:09:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33936 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244298AbiHZPJA (ORCPT ); Fri, 26 Aug 2022 11:09:00 -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 A3607DD4D5 for ; Fri, 26 Aug 2022 08:08:30 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id q18-20020a056402519200b0043dd2ff50feso1231432edd.9 for ; Fri, 26 Aug 2022 08:08:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=hggbZ+cOdGgnZCdhDJpRznFT1vHDu/CChFRNqftxg0A=; b=EKDv/PKgOR34tp0oFw4TL9dVZHFwqGbAnQQTavn0Xb62dbzFUPj4AI2a2e29t52VSJ yaoFonp9v5PbGfPtOW6Uh8tNheGfPxvg/MU0asqfbMaiuOZNDWdFpQ94r1Zh8FOVrEnm JQ2E1I0YGWBkaD0qcUuZ5JeHn1KPGod8KQb1wyugpmuOuxG8ECd3XnLWSqUu2g0tGj2b dmEeFFRLu/AOYLusP+PU+EKyFNbiVWULVZ42tPOD6npOeAf/aXtmAiOsXIVBCl3qVl/7 zwuG92ejO3Uyng0LtzupdNhB8U3bxwl7uZHemEXKWAHihOQA6rP2bYc0y6ybBLFxrVc/ /QKQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=hggbZ+cOdGgnZCdhDJpRznFT1vHDu/CChFRNqftxg0A=; b=DX8/i3XH9dvhUqmK8jmpwQqX+a7MIpNNE+hQVX5csPGTVlJckE00QekntnZTTzqY/Z 2jjbkViXroiXA+ho/xSixEp2iXEUXAxuQuydAYMT7Lpsd56FgCfIHZU+HEi2YV7toufo yJt6ZdqPqiYqolmwAdik8iWYsA87uLK7qgp049CGGscug/tg2nWH3cmQg7LMkCcj7Mci NOjSNgA8SCdMs1Wiowm70FDha2gqHyw+2pwNL3D4TC8D+l6y6NItYBk+TB63XrVUdlNM WnhMvD9neMJq4kWXPf5b3bljzQ85FJlgTmLfaCPahYovIo8iIBwIR6RRjJLYxAK6+WmS HxVQ== X-Gm-Message-State: ACgBeo1k5HS9s54+Eo6XXxhEr224VGB0OtsYM/gC/sEwZxsiSS6SbeoO EUGuEycytZWfJTGacDNoBFiMaQH2Jc8= X-Google-Smtp-Source: AA6agR5RUyGEpeyaVgz2pyBw8iJVbCbQSsoESYlrJth4vdCU9aTTXtJ3gDZxudBR1HRU3xhSKcYSnHDQJUk= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:360d:b0:445:bd16:803b with SMTP id el13-20020a056402360d00b00445bd16803bmr6959224edb.318.1661526509859; Fri, 26 Aug 2022 08:08:29 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:29 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-7-glider@google.com> Subject: [PATCH v5 06/44] kmsan: add ReST documentation From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 v5: -- mention CONFIG_KMSAN_CHECK_PARAM_RETVAL, drop mentions of cpu_entry_area -- add SPDX license -- address Marco Elver's comments: reorganize doc structure, fix minor nits Link: https://linux-review.googlesource.com/id/I751586f79418b95550a83c6035c= 650b5b01567cc --- Documentation/dev-tools/index.rst | 1 + Documentation/dev-tools/kmsan.rst | 427 ++++++++++++++++++++++++++++++ 2 files changed, 428 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..2a53a801198cb --- /dev/null +++ b/Documentation/dev-tools/kmsan.rst @@ -0,0 +1,427 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. Copyright (C) 2022, Google LLC. + +=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 Kernel Memory Sanitizer (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=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. + +Usage +=3D=3D=3D=3D=3D + +Building the kernel +------------------- + +In order to build a kernel with KMSAN you will need a fresh Clang (14.0.6+= ). +Please refer to `LLVM documentation`_ for the instructions on how to build= Clang. + +Now configure and build the kernel with CONFIG_KMSAN enabled. + +Example report +-------------- + +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 third stack trace corresponds to the place +where this variable was created. + +The first stack trace 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. + +A use of uninitialized value ``v`` is reported by KMSAN in the following c= ases: + - in a condition, e.g. ``if (v) { ... }``; + - in an indexing or pointer dereferencing, e.g. ``array[v]`` or ``*v``; + - when it is copied to userspace or hardware, e.g. ``copy_to_user(..., &v= , ...)``; + - when it is passed as an argument to a function, and + ``CONFIG_KMSAN_CHECK_PARAM_RETVAL`` is enabled (see below). + +The mentioned cases (apart from copying data to userspace or hardware, whi= ch is +a security issue) are considered undefined behavior from the C11 Standard = point +of view. + +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 interfere with = some +low-level code (e.g. that marked with ``noinstr`` which implicitly adds +``__no_sanitize_memory``). + +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). + +Support +=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`_. + +The runtime library only supports x86_64 at the moment. + +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 as they are used al= ong +the code. When needed, instrumentation code invokes the runtime library in +``mm/kmsan/`` to persist shadow values. + +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 mapped to t= hem. +This origin describes the point in program execution at which the uninitia= lized +value was created. Every origin is associated with either the full allocat= ion +stack (for heap-allocated memory), or the function containing the uninitia= lized +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. Wh= en 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 origin of= the +result is one of the origins corresponding to any of the uninitialized inp= uts. +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 never be 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/nstrumentation.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. + +Handling locals +~~~~~~~~~~~~~~~ + +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 (unless the parameters are checked immediately by +``CONFIG_KMSAN_CHECK_PARAM_RETVAL``). + +Passing uninitialized values to functions +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Clang's MemorySanitizer instrumentation has an option, +``-fsanitize-memory-param-retval``, which makes the compiler check function +parameters passed by value, as well as function return values. + +The option is controlled by ``CONFIG_KMSAN_CHECK_PARAM_RETVAL``, which is +enabled by default to let KMSAN report uninitialized values earlier. +Please refer to the `LKML discussion`_ for more details. + +Because of the way the checks are implemented in LLVM (they are only appli= ed to +parameters marked as ``noundef``), not all parameters are guaranteed to be +checked, so we cannot give up the metadata storage in ``kmsan_context_stat= e``. + +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 use of a value the compiler emits a shadow check that calls +``__msan_warning()`` in the case that value is poisoned:: + + 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. + + +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. Consequently, if a memory access crosses the +boundary of a memory block, accesses to shadow/origin memory may potential= ly +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. + +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 +.. _LKML discussion: https://lore.kernel.org/all/20220614144853.3693273-1-= glider@google.com/ --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 0C460ECAAA3 for ; Fri, 26 Aug 2022 15:09:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245212AbiHZPJj (ORCPT ); Fri, 26 Aug 2022 11:09:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33940 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244402AbiHZPJC (ORCPT ); Fri, 26 Aug 2022 11:09:02 -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 33123DD4E6 for ; Fri, 26 Aug 2022 08:08:34 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id gt9-20020a1709072d8900b0073d82402ea6so731360ejc.21 for ; Fri, 26 Aug 2022 08:08:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=c5NepUxkZ67sJe7jHUeDkh2lejA2rZ0n/lgzGJfAW+w=; b=c+6A8OMgE+PXXvaKjkvUnzf0Zny9FaGQw3ITZ0eOqhvk/xJ6RvxfKh+stOxXyatXl4 YGr0F0FGxuPcv8CUWTObk59qFjdxmNbRa0oHquDksvKKfT8Zu2vHF6G0vca6kOpAbhNI OVOEZTiTMx/xUIeNXpsat3eCswFWmSuMpYNt42aS00HKw95twaAXWDw2g1FqoKpczn16 IuVC8oufvBy3n96QICaiFTQbEIjqBDPQxH/4XN690eGkbiZ3y/ft7KJ0uT7Yb+5MevGJ DRahR3sL+vhkXEP7eUoI9WqyhhSukcLsMWy7BqvewYy5XGfr72OPIP7WRVR5q3FgsYZn IVMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=c5NepUxkZ67sJe7jHUeDkh2lejA2rZ0n/lgzGJfAW+w=; b=WeHv4rZuqj6WBSof5IVNxUbmNXUk+QYYI9HepB/Ve85/EpteGbNocaWA6VuNH2eTb3 5phi7rmCUFRVGyP6w5uFdpYHtRQH1z5DR6FpTh4NdCBpRD34HJHbTkGSTO8qDpDtN2fP rVI7Vq8hRLaIfQxrd6DyqrBbhxzh61cS2BWNqfPD+q8CSvGoC8oC9y/jYVit91+IG1Sq O7pKNvSAv1+6JIDkVZphRGWDpUlmCyFuZwRHR+CeVJGr7JePlnYCs7S3eX0XGAQh8jXZ 5lFF5MTT56P9pEuqzHDbWXabMt1ujyUVkppdh1T6N5aTRqjhp1weZJxy67Jm9+IVZ/vV vdKg== X-Gm-Message-State: ACgBeo0PCmpDnRDxnAYSPHBg1x8Cdy6MJ5nHwV7s5Vf52LwrCLMCWMqb PkYFuL7bkoxywI0jbfLuUh5QE6IqoNg= X-Google-Smtp-Source: AA6agR5ehbhUugsFXAPBIbmUJl2ccI1z6E6toZVNB9pK3XsABZI5EGu5QKmG8MsBqiQScrt+e+ok3n5vJiE= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:515:b0:447:780c:39d6 with SMTP id m21-20020a056402051500b00447780c39d6mr7244136edv.265.1661526512626; Fri, 26 Aug 2022 08:08:32 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:30 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-8-glider@google.com> Subject: [PATCH v5 07/44] kmsan: introduce __no_sanitize_memory and __no_kmsan_checks From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 Reviewed-by: Marco Elver --- 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 c84fec767445d..4fa0cc4cbd2c8 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 9b157b71036f1..f55a37efdb974 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -114,6 +114,12 @@ #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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 C50ABECAAD5 for ; Fri, 26 Aug 2022 15:09:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245361AbiHZPJq (ORCPT ); Fri, 26 Aug 2022 11:09:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244410AbiHZPJC (ORCPT ); Fri, 26 Aug 2022 11:09:02 -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 0C2EBDD4F0 for ; Fri, 26 Aug 2022 08:08:36 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id nc8-20020a1709071c0800b0073d9044ff27so715591ejc.4 for ; Fri, 26 Aug 2022 08:08:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=TLtEZ0bDABRCjn67uEnKqh55BiGh6mAGtPfpqU3Dom0=; b=XhlU5hNd0e3S9HPBMmJkefc8yx08LwmA0SrbD/8z4iCrhfOsJcZduc1PlOL9efVBc+ RqztXd6/u4p+K40pJYJ4MKo6W7YSwm2TGNfQJRg+spj7KYsPClZuKVg0K7kt5K6whqKk q+NjffiftBk+4Wc6g4Tz0BBUvyrlit9JdAIemyH8qENuefh4JnuhzYQuq/s4MXy2lHoL NjoHCmqDqQlUi8tcUV7ZMIQKkT1OxE2DmCvSQcE4JHvpg4oQKQDno1JEzzGIKstmVxfI M0cRhGmxUmpadUGkfzrVjEWgWPnBig+aEKw2Ua3xaSSd45CO/SHC+zQxCgI2IVeAmV7R JiAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=TLtEZ0bDABRCjn67uEnKqh55BiGh6mAGtPfpqU3Dom0=; b=eX2bsSrNd+l7lW99yW4JkiarXsn/CRbxne/bu0hoiEhtjGBAq+9A0JmruxzWFcvdr5 Tg6gAw2qzwtJPmz82WVDAZJYaOX+L/FJG1UZ6bAHJuSgZG24uIi0tKYLCLKO0+UPA8N0 uTT1MdZivsPd4a8gHxUEW6yWJY/Td98SL2OtIh94DX8NNZQo4ZAi0rrPgfj1hfDk2Xuk 9WjQzdL3DqvYid6E0rFtUqnXoIatWSBcFU40NL+NX0Ew7b9kW5eJJe+Wnzx+od/FK8no 3m+seZLhHczUPHdkeuoePsjMCr0XrGR1KfusWMqushDkwWj7Zye3gKnmfD3FqpJGM+W1 uLlA== X-Gm-Message-State: ACgBeo1HnfNVksNHgAGIz6BuYI/z81IvY7lCzWbMNj3Md5VZT2nFQbGr mtCrYM6YGAMErZO7NSfTQhOeBzZMw14= X-Google-Smtp-Source: AA6agR6QdK8Prck1Efax3JC3LSwW7ZoPOT0nuqvyH6CShWmZZX9DGTqKWmC6+Ghh+6F66GZY1zvqUreveU8= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a17:906:9752:b0:738:364a:4ac with SMTP id o18-20020a170906975200b00738364a04acmr5783646ejy.759.1661526515449; Fri, 26 Aug 2022 08:08:35 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:31 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-9-glider@google.com> Subject: [PATCH v5 08/44] kmsan: mark noinstr as __no_sanitize_memory From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 Reviewed-by: Marco Elver --- 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 4f2a819fd60a3..015207a6e2bf5 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -229,7 +229,8 @@ 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 65868ECAAD5 for ; Fri, 26 Aug 2022 15:10:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245675AbiHZPKV (ORCPT ); Fri, 26 Aug 2022 11:10:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33958 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244045AbiHZPJU (ORCPT ); Fri, 26 Aug 2022 11:09:20 -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 BC3DCDC08C for ; Fri, 26 Aug 2022 08:08:38 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id w20-20020a05640234d400b00447e6ffefccso1264155edc.0 for ; Fri, 26 Aug 2022 08:08:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=lZyR+/TbY71+6irDHrQVY8i8lV0LAE0DR0x5Sx//ziQ=; b=Ofrs8PCMHX+W0ceEYWnDzVx1uzp/bWz8GLaWKdo+wAqOx3sPZu6pI92iq0IULzGOQ8 VJ09OsHIUk+49s1paxcvdc/dQgoZURGCS4X6UxVQKGmyCn/fzomHAQt3pDibyyvopGw+ A204SQq3udS4olps/yoQNs/HdBDLMH/XYtFo5t7S3WbS0/Mi6jEQiCtdTGIheelU/NKQ ODyynPxQ+JC42TN6qhou33wAGXEzHzmJj/qEXAgKq4QXYccBrT+Ih7NpvsAuafykD+5Y +aYVMqZk7TNUIRRwqC7Wdqslm1Z8gXmVvziP4uuhA49TmwX3KTg2b8vw2WCFS2T1Wo1D S3QQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=lZyR+/TbY71+6irDHrQVY8i8lV0LAE0DR0x5Sx//ziQ=; b=gPpzKCYvFUMAwa9Am5DFb9ZqG3ubQQ9liRrt3Pr11vqXKHX/m5jnWWHVvBnaK172fw 6RmKK4Q34qHWw5M9r7VyRTzErxnLSIugr6RGiVFUyPb2qX9AYEDr4uXxpdpPkntJRemC cj7Mbf/6FetRK+NjYPPcDfhqql6ikg6py5FQDAijtOKs9ZLgDm1T+SUjyWtCd87nyRv8 QuRx0/j/86qEgYzrsuP2brQxIHxa+XQdNnRmDnptyBtnhJzib4+WiuJbAVLgDgBLhDk3 aE+gpTwP5EnPCIJhHhscnXH2IVcwphU1gf8d1zWIqgZqvlRzK7iov6Jwj3GiaMbo55iz fAfg== X-Gm-Message-State: ACgBeo1ssAaZH0Lln2d1tf98eyuSNdUR7vsa+6JySli5N1UiQW+Ax/OD htcCwXNCkNF+BlEBTEskMdHr/OpNcZQ= X-Google-Smtp-Source: AA6agR6DZmZvABSNd8NirMJa2iJguxZBNB8hGvX5VWCga9N1u2wq6DvLGXRRSlQxms71XTCN2etlpU9v9zU= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a17:906:f88f:b0:731:463d:4b15 with SMTP id lg15-20020a170906f88f00b00731463d4b15mr5703796ejb.299.1661526518263; Fri, 26 Aug 2022 08:08:38 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:32 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-10-glider@google.com> Subject: [PATCH v5 09/44] x86: kmsan: pgtable: reduce vmalloc space From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 v5: -- add comment for VMEMORY_END Link: https://linux-review.googlesource.com/id/I9d8b7f0a88a639f1263bc693cbd= 5c136626f7efd --- arch/x86/include/asm/pgtable_64_types.h | 47 ++++++++++++++++++++++++- arch/x86/mm/init_64.c | 2 +- 2 files changed, 47 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm= /pgtable_64_types.h index 70e360a2e5fb7..04f36063ad546 100644 --- a/arch/x86/include/asm/pgtable_64_types.h +++ b/arch/x86/include/asm/pgtable_64_types.h @@ -139,7 +139,52 @@ 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) +/* + * End of the region for which vmalloc page tables are pre-allocated. + * For non-KMSAN builds, this is the same as VMALLOC_END. + * For KMSAN builds, VMALLOC_START..VMEMORY_END is 4 times bigger than + * VMALLOC_START..VMALLOC_END (see below). + */ +#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 0fe690ebc269b..39b6bfcaa0ed4 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 7F387ECAAD6 for ; Fri, 26 Aug 2022 15:10:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244359AbiHZPK3 (ORCPT ); Fri, 26 Aug 2022 11:10:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244667AbiHZPJW (ORCPT ); Fri, 26 Aug 2022 11:09:22 -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 D3FBADD746 for ; 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Fri, 26 Aug 2022 08:08:41 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:33 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-11-glider@google.com> Subject: [PATCH v5 10/44] libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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. This change leads to increased memory consumption of the nvdimm driver, regardless of whether the kernel is built with KMSAN or not. Signed-off-by: Alexander Potapenko Reviewed-by: Marco Elver --- 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 ec5219680092d..85ca5b4da3cf3 100644 --- a/drivers/nvdimm/nd.h +++ b/drivers/nvdimm/nd.h @@ -652,7 +652,7 @@ 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 0e92ab4b32833..61af072ac98f9 100644 --- a/drivers/nvdimm/pfn_devs.c +++ b/drivers/nvdimm/pfn_devs.c @@ -787,7 +787,7 @@ 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 C25EFECAAA3 for ; Fri, 26 Aug 2022 15:11:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243969AbiHZPLY (ORCPT ); Fri, 26 Aug 2022 11:11:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33942 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243923AbiHZPJX (ORCPT ); Fri, 26 Aug 2022 11:09:23 -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 76376DD75E for ; Fri, 26 Aug 2022 08:08:45 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id i6-20020a05640242c600b00447c00a776aso1248531edc.20 for ; Fri, 26 Aug 2022 08:08:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:from:to:cc; bh=eB9ouCXgP1qqZdJonKnbXitFduJalY0opMmh3eEt0B8=; b=ZaEUcWpiEGxqcsbVGYdL8XcUyUT4za7rB58z2H/7YtDFty4EkDWPaPyvoKcvVACfr4 +mJm5xXZPATcxsAA6H1XsVkt/9iSXd9BzBVf5dAjgGJzAuv5mq5g++szRD9Pr3iQ/S91 1WX5KlYT4DRSsq8TKzGJGjI8Ob8gljM4z7rM3LoWynsuqTJuSFXNBdThbpEZ8fzk1Q5G KPKZQRwxi+PVHUJndiv220RCShfAsrDH1vF+wMtz/Z6J+Qkbm+3yFbbHXBoWkMZQV4Uf 8B3SgHgwl76AJKiGEdcgeX5W/bwwHbTSbduJIxHGMNsjY/l2y/kTAwAyBYyYtM64y0NY LAzw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:x-gm-message-state:from:to:cc; bh=eB9ouCXgP1qqZdJonKnbXitFduJalY0opMmh3eEt0B8=; b=43LHESi1sQM3LVxTH/1jNPNrgHVG/EiIjp7p/yKwGSMDTbkhm/Y12M3koksjJjEQB5 4MXg4aSZC5lDx5rISQZtQl6hhYII+9btawsYKTNwsF8WbucsG1dLCfY7bqUOwdWUptcb +PWjjwx7F8NSFb6SqD1FJSgE/1PzPuXwT/2QuUzAnxeuS9jN15saubvZiuIVieeAzSzX 6A/yJvUsOudjOHAktqWguerxMAzAK3/wFfpY7Hki0fI6qF/qXrBG0qTQ1cPQ2n9GVele b8CetSHEVaSCHHEOyCZwv6Ql+pb4RceQ5rk9cJPOXYXA5X9UUNiAL8STvvZoeqhvGygL OPCQ== X-Gm-Message-State: ACgBeo22vwrDHLC9SnsgBrHipD85lhhRGTboIB2n3RF+v0TJ93o1Q4zK FHp7aW0VrWbDUMvVYTWG4FKiIRjz1tc= X-Google-Smtp-Source: AA6agR6xcDnGo0oDwRX4VmpX9joMoikK/+wGua6z3xhzdQrYIgYVO7wwmJO/8eBWSQhdfDfgawYmdOtzFw0= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:aa7:d04a:0:b0:447:e24a:5cc9 with SMTP id n10-20020aa7d04a000000b00447e24a5cc9mr3049319edo.244.1661526523708; Fri, 26 Aug 2022 08:08:43 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:34 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-12-glider@google.com> Subject: [PATCH v5 11/44] kmsan: add KMSAN runtime core From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 Acked-by: Marco Elver --- 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() v3: -- print build IDs in reports where applicable -- drop redundant filter_irq_stacks(), unpoison the local passed to __stac= k_depot_save() -- remove a stray BUG() v4: (mostly fixes suggested by Marco Elver) -- add missing SPDX headers -- move CC_IS_CLANG && CLANG_VERSION under HAVE_KMSAN_COMPILER -- replace occurrences of |var| with @var -- reflow KMSAN_WARN_ON(), fix comments -- remove x86-specific code from shadow.c to improve portability -- convert kmsan_report_lock to raw spinlock -- add enter_runtime/exit_runtime around kmsan_internal_memmove_metadata() -- remove unnecessary include from kmsan.h (reported by ) -- introduce CONFIG_KMSAN_CHECK_PARAM_RETVAL (on by default), which maps to -fsanitize-memory-param-retval and makes KMSAN eagerly check values passed as function parameters and returned from functions. v5: -- do not return dummy shadow from within runtime -- preserve shadow when calling memcpy()/memmove()/memset() -- reword some code comments -- reapply clang-format, switch to modern style for-loops -- move kmsan_internal_is_vmalloc_addr() and kmsan_internal_is_module_addr() to the header -- refactor lib/Kconfig.kmsan as suggested by Marco Elver -- remove forward declaration of `struct page` from this patch Link: https://linux-review.googlesource.com/id/I9b71bfe3425466c97159f9de006= 2e5e8e4fec866 --- Makefile | 1 + include/linux/kmsan-checks.h | 64 +++++ include/linux/kmsan.h | 44 ++++ include/linux/mm_types.h | 12 + include/linux/sched.h | 5 + lib/Kconfig.debug | 1 + lib/Kconfig.kmsan | 50 ++++ mm/Makefile | 1 + mm/kmsan/Makefile | 23 ++ mm/kmsan/core.c | 448 +++++++++++++++++++++++++++++++++++ mm/kmsan/hooks.c | 66 ++++++ mm/kmsan/instrumentation.c | 307 ++++++++++++++++++++++++ mm/kmsan/kmsan.h | 203 ++++++++++++++++ mm/kmsan/report.c | 211 +++++++++++++++++ mm/kmsan/shadow.c | 147 ++++++++++++ scripts/Makefile.kmsan | 8 + scripts/Makefile.lib | 9 + 17 files changed, 1600 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 c7705f7496012..4552a15bfa4fe 100644 --- a/Makefile +++ b/Makefile @@ -1015,6 +1015,7 @@ 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_RANDSTRUCT) +=3D scripts/Makefile.randstruct 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..e578c9627b641 --- /dev/null +++ b/include/linux/kmsan.h @@ -0,0 +1,44 @@ +/* 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 + +#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 cf97f3884fda2..8be4f34cb8caa 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -223,6 +223,18 @@ 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 e7b2f8a5c711c..ca4b434bc778e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -1355,6 +1356,10 @@ 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 072e4b289c13e..1f80db29728a7 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -971,6 +971,7 @@ 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..5b19dbd34d76e --- /dev/null +++ b/lib/Kconfig.kmsan @@ -0,0 +1,50 @@ +# SPDX-License-Identifier: GPL-2.0-only +config HAVE_ARCH_KMSAN + bool + +config HAVE_KMSAN_COMPILER + # Clang versions <14.0.0 also support -fsanitize=3Dkernel-memory, but not + # all the features necessary to build the kernel with KMSAN. + depends on CC_IS_CLANG && CLANG_VERSION >=3D 140000 + def_bool $(cc-option,-fsanitize=3Dkernel-memory -mllvm -msan-disable-chec= ks=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 + 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. + +if KMSAN + +config HAVE_KMSAN_PARAM_RETVAL + # -fsanitize-memory-param-retval is supported only by Clang >=3D 14. + depends on HAVE_KMSAN_COMPILER + def_bool $(cc-option,-fsanitize=3Dkernel-memory -fsanitize-memory-param-r= etval) + +config KMSAN_CHECK_PARAM_RETVAL + bool "Check for uninitialized values passed to and returned from function= s" + default y + depends on HAVE_KMSAN_PARAM_RETVAL + help + If the compiler supports -fsanitize-memory-param-retval, KMSAN will + eagerly check every function parameter passed by value and every + function return value. + + Disabling KMSAN_CHECK_PARAM_RETVAL will result in tracking shadow for + function parameters and return values across function borders. This + is a more relaxed mode, but it generates more instrumentation code and + may potentially report errors in corner cases when non-instrumented + functions call instrumented ones. + +endif diff --git a/mm/Makefile b/mm/Makefile index 9a564f8364035..cce88e5b6d76f 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -89,6 +89,7 @@ obj-$(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..550ad8625e4f9 --- /dev/null +++ b/mm/kmsan/Makefile @@ -0,0 +1,23 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for KernelMemorySanitizer (KMSAN). +# +# +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..a5dec6e62b4ef --- /dev/null +++ b/mm/kmsan/core.c @@ -0,0 +1,448 @@ +// 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); + + /* 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; + /* + * @entries is a local var in non-instrumented code, so KMSAN does not + * know it is initialized. Explicitly unpoison it to avoid false + * positives when __stack_depot_save() passes it to instrumented code. + */ + kmsan_internal_unpoison_memory(entries, sizeof(entries), false); + 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; + + 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); + KMSAN_WARN_ON(true); + } + 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 (int 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 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 (int 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; +} 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..280d154132684 --- /dev/null +++ b/mm/kmsan/instrumentation.c @@ -0,0 +1,307 @@ +// 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); + +/* + * KMSAN instrumentation pass replaces LLVM memcpy, memmove and memset + * intrinsics with calls to respective __msan_ functions. We use + * get_param0_metadata() and set_retval_metadata() to store the shadow/ori= gin + * values for the destination argument of these functions and use them for= the + * functions' return values. + */ +static inline void get_param0_metadata(u64 *shadow, + depot_stack_handle_t *origin) +{ + struct kmsan_ctx *ctx =3D kmsan_get_context(); + + *shadow =3D *(u64 *)(ctx->cstate.param_tls); + *origin =3D ctx->cstate.param_origin_tls[0]; +} + +static inline void set_retval_metadata(u64 shadow, depot_stack_handle_t or= igin) +{ + struct kmsan_ctx *ctx =3D kmsan_get_context(); + + *(u64 *)(ctx->cstate.retval_tls) =3D shadow; + ctx->cstate.retval_origin_tls =3D origin; +} + +/* Handle llvm.memmove intrinsic. */ +void *__msan_memmove(void *dst, const void *src, uintptr_t n) +{ + depot_stack_handle_t origin; + void *result; + u64 shadow; + + get_param0_metadata(&shadow, &origin); + 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_enter_runtime(); + kmsan_internal_memmove_metadata(dst, (void *)src, n); + kmsan_leave_runtime(); + + set_retval_metadata(shadow, origin); + return result; +} +EXPORT_SYMBOL(__msan_memmove); + +/* Handle llvm.memcpy intrinsic. */ +void *__msan_memcpy(void *dst, const void *src, uintptr_t n) +{ + depot_stack_handle_t origin; + void *result; + u64 shadow; + + get_param0_metadata(&shadow, &origin); + 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; + + kmsan_enter_runtime(); + /* Using memmove instead of memcpy doesn't affect correctness. */ + kmsan_internal_memmove_metadata(dst, (void *)src, n); + kmsan_leave_runtime(); + + set_retval_metadata(shadow, origin); + return result; +} +EXPORT_SYMBOL(__msan_memcpy); + +/* Handle llvm.memset intrinsic. */ +void *__msan_memset(void *dst, int c, uintptr_t n) +{ + depot_stack_handle_t origin; + void *result; + u64 shadow; + + get_param0_metadata(&shadow, &origin); + 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(); + + set_retval_metadata(shadow, origin); + 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..6b9deee3b7f32 --- /dev/null +++ b/mm/kmsan/kmsan.h @@ -0,0 +1,203 @@ +/* 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 or KMSAN runtime function is invoked, it may make a + * call to instrumented code and eventually call itself recursively. To av= oid + * that, we guard the runtime entry regions with + * kmsan_enter_runtime()/kmsan_leave_runtime() and exit the hook if + * kmsan_in_runtime() is true. + * + * Non-runtime code may occasionally get executed in nested IRQs from the + * runtime code (e.g. when called via smp_call_function_single()). Because= some + * KMSAN routines may take locks (e.g. for memory allocation), we conserva= tively + * bail out instead of calling them. To minimize the effect of this (poten= tially + * missing initialization events) kmsan_in_runtime() is not checked in + * non-blocking runtime functions. + */ +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); + +struct page *kmsan_vmalloc_to_page_or_null(void *vaddr); + +/* + * kmsan_internal_is_module_addr() and kmsan_internal_is_vmalloc_addr() are + * non-instrumented versions of is_module_address() and is_vmalloc_addr() = that + * are safe to call from KMSAN runtime without recursion. + */ +static inline bool kmsan_internal_is_module_addr(void *vaddr) +{ + return ((u64)vaddr >=3D MODULES_VADDR) && ((u64)vaddr < MODULES_END); +} + +static inline bool kmsan_internal_is_vmalloc_addr(void *addr) +{ + return ((u64)addr >=3D VMALLOC_START) && ((u64)addr < VMALLOC_END); +} + +#endif /* __MM_KMSAN_KMSAN_H */ diff --git a/mm/kmsan/report.c b/mm/kmsan/report.c new file mode 100644 index 0000000000000..64e061f7da496 --- /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_RAW_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 pos =3D 0, len =3D strlen(descr); + + for (int 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(" %pSb\n", pc1); + if (pc2) + pr_err(" %pSb\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 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(); + raw_spin_lock(&kmsan_report_lock); + 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 %pSb\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); + raw_spin_unlock(&kmsan_report_lock); + 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..acc5279acc3be --- /dev/null +++ b/mm/kmsan/shadow.c @@ -0,0 +1,147 @@ +// 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 "../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); + +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) + 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; + + 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; + + return (is_origin ? origin_ptr_for(page) : shadow_ptr_for(page)) + off; +} diff --git a/scripts/Makefile.kmsan b/scripts/Makefile.kmsan new file mode 100644 index 0000000000000..b5b0aa61322ec --- /dev/null +++ b/scripts/Makefile.kmsan @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0 +kmsan-cflags :=3D -fsanitize=3Dkernel-memory + +ifdef CONFIG_KMSAN_CHECK_PARAM_RETVAL +kmsan-cflags +=3D -fsanitize-memory-param-retval +endif + +export CFLAGS_KMSAN :=3D $(kmsan-cflags) diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 3fb6a99e78c47..ac32429e93b73 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -157,6 +157,15 @@ _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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 273BDECAAD4 for ; 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Fri, 26 Aug 2022 08:08:46 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:35 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-13-glider@google.com> Subject: [PATCH v5 12/44] kmsan: disable instrumentation of unsupported common kernel code From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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. Signed-off-by: Alexander Potapenko Reviewed-by: Marco Elver --- v4: -- This patch was previously part of "kmsan: disable KMSAN instrumentation for certain kernel parts", but was split away per Mark Rutland's request. v5: -- remove unnecessary comment belonging to another patch Link: https://linux-review.googlesource.com/id/I41ae706bd3474f074f6a870bfc3= f0f90e9c720f7 --- drivers/firmware/efi/libstub/Makefile | 1 + kernel/Makefile | 1 + kernel/locking/Makefile | 3 ++- lib/Makefile | 3 +++ 4 files changed, 7 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 318789c728d32..d754e0be1176d 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -38,6 +38,7 @@ 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 $(CC_FLAGS_FTRACE) diff --git a/lib/Makefile b/lib/Makefile index 5927d7fa08063..22c064b61b3be 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -275,6 +275,9 @@ obj-$(CONFIG_POLYNOMIAL) +=3D polynomial.o CFLAGS_stackdepot.o +=3D -fno-builtin obj-$(CONFIG_STACKDEPOT) +=3D stackdepot.o KASAN_SANITIZE_stackdepot.o :=3D n +# In particular, instrumenting stackdepot.c with KMSAN will result in infi= nite +# recursion. +KMSAN_SANITIZE_stackdepot.o :=3D n KCOV_INSTRUMENT_stackdepot.o :=3D n =20 obj-$(CONFIG_REF_TRACKER) +=3D ref_tracker.o --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 B6DE2ECAAD4 for ; Fri, 26 Aug 2022 15:10:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244907AbiHZPKm (ORCPT ); Fri, 26 Aug 2022 11:10:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35320 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244314AbiHZPJ1 (ORCPT ); Fri, 26 Aug 2022 11:09:27 -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 E583FDDA87 for ; Fri, 26 Aug 2022 08:08:50 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id c14-20020a05640227ce00b0043e5df12e2cso1236239ede.15 for ; Fri, 26 Aug 2022 08:08:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=PmohPhKomZXd1zOAWK/EQjp0UhZ3tSbnWnyq8ud/fAU=; b=YJO4Xg0+O4fDaxcbYp1umz/9KOZq6MT64iPBuvb1Eyk0CRlXy5BoZxooWMgHq81Mww aAkaFVvfJmx8okxcpaJTFDvGl68dPKJ+48I8mfAqwXsEanHocOAaCh/MGEgmAYwBPoyU B98RoAIMKx99hewKWZNnFsrHAzTgDEPPakAw+ENqyBC9iSPWmrVjYUMFS5UztA5Jrts/ NAmFaPfKOWhmTiRrueAff3+7UOYpVyTReHij2nZk2PTf9O6wfSScGw/khRnRflK4HTor aK26uUCVllQrwo/IEachNt1mk39lrVOLqFljJSHkCaPXcdzGpzQO93EM3hejm5qh5wEj xnmQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=PmohPhKomZXd1zOAWK/EQjp0UhZ3tSbnWnyq8ud/fAU=; b=h/7dWpsOrc3D03xnnO6/9j3ukb0IqqLgW39zt1OC6x2KBTnfIJywOkKmVCQ7p4m922 LUba1OYrd2mfTic34IdxJDZbRXEaMKtrbPIKpnQ9Qvp+LBgYEA8XnNTMP7J+P2bYNnAt spb59BU4Ngu21QRX6YvsYFlOJ/MWFo8Y5YOzuJZnVXXzoFBFF4L5oKPSj6y17sOPE3z8 WKN05Itzb1mkEIdCx9evccnVE6MjmGnSKHGG7vO4e5TQlDhBa5ddmMJZZdQBTVcbsB0J WJ+FmvCHdNlOzVR8e9zcqBCWmHEn4ISI6zSUNwsnDoGaR7Tq3VRDxsDBVk/7xg+6Rd/w sL4A== X-Gm-Message-State: ACgBeo33aXteh/+UxJg7HqC8Tz+Hlg0F4YErpIfK0H9syGr2bZZSnoU6 9344SAhHSU0oZx5s7r0FSHrIEzcW8MM= X-Google-Smtp-Source: AA6agR7e2paC/ZuzvRhAHjB4767/oTAx7KXCr2XuebS6jhDF8RYl+Uz9hljfZfbpg8cNZSTTP2UQ/IVJ12o= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a17:907:2cd0:b0:73d:d80c:b51f with SMTP id hg16-20020a1709072cd000b0073dd80cb51fmr4282876ejc.619.1661526528970; Fri, 26 Aug 2022 08:08:48 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:36 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-14-glider@google.com> Subject: [PATCH v5 13/44] MAINTAINERS: add entry for KMSAN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 --- v5: -- add arch/*/include/asm/kmsan.h Link: https://linux-review.googlesource.com/id/Ic5836c2bceb6b63f71a60d3327d= 18af3aa3dab77 --- MAINTAINERS | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index 9d7f64dc0efe8..3bae9c4c2b73d 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -11369,6 +11369,19 @@ 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: arch/*/include/asm/kmsan.h +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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 CC9BAECAAD4 for ; Fri, 26 Aug 2022 15:10:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244056AbiHZPK4 (ORCPT ); Fri, 26 Aug 2022 11:10:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33910 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245408AbiHZPKB (ORCPT ); Fri, 26 Aug 2022 11:10:01 -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 1EC1DDDAA7 for ; Fri, 26 Aug 2022 08:08:53 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id mp41-20020a1709071b2900b0073d84b11981so730460ejc.23 for ; Fri, 26 Aug 2022 08:08:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=RCEJUrdGaZnDzkCVeq8BsOQ2VOxKVJNx7oe/faTwpqA=; b=DoBVgTeGHV+u4ohZMjhohR9m7JZpg5bj+EOWAguhfJxw2njpO0bZUyxV8bU0tZn0Ra g4GMhUWzdfTwnZoVAfqv/IdaiB7JqDdJRTOE0WCN13NA9+T3eSW1XFXvQP71IHqd2jau fDN/vaIVtdpziHVBYi42qzwTu4xZLCKsOWysr/uioRDhab3l/hrj2S/vWl5g1PHoNlq/ x4jy0FkjbzwiKmzmpAvufx4skS2+F9vqUJjiXlYirlGW6/nMQAxovyBg53kdNZamtimt YzDX3SBfPazo7/1hJANLwD98EfVSr0TuJWea7uopoguN5rNEeopAcAF0FN5+ztQ7PxGg 1KDQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=RCEJUrdGaZnDzkCVeq8BsOQ2VOxKVJNx7oe/faTwpqA=; b=Kj0+rMJeCLYsV1oAcyRcJYwbtF+8QNqnShtZmkSHb2xgqJCa/an9IG4SSL9SjyJIpy l/c0ueZ3Cka8mITrrG0ocHci8yLSTjrjd2lK2WE9f+k0QMFEc8Pmmj58EfkvV3VmN/mm chAjMcU0+NUik+BGMpbROE5hxqJ8EnYUB9L6+bAaSfvLZA+eDtOYMUtrex2VGiOvGvPj 6IEUuo/b+IfmSRGePAeKMrukcnVIJQiW14worlBrVY3rm07MYuwUNMtWT2GqgUZQfNkA OQvcsGjrlnkAGuujbRpOSOYHRdkPAUh/RfXeYpI3c1WrZJG+qDxD+xxkTw5aPHSLB2ok +qmA== X-Gm-Message-State: ACgBeo295zrzx8Dt3/3X91SB9gr6SLYsOX2MobpfRFiMZ//0phDVVMK4 u3tscM30d0/DQ3yQaQJFZVn8PkJHbtA= X-Google-Smtp-Source: AA6agR5TJ2215a/FX4xfXZffmhokPd+WXLuXNU73CeC2DKzV0N0DB4LEJ7M+hq0lpB1gpBiSGrqZAF8M6ss= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a17:906:cc15:b0:73d:d87f:f039 with SMTP id ml21-20020a170906cc1500b0073dd87ff039mr4286773ejb.253.1661526532079; Fri, 26 Aug 2022 08:08:52 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:37 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-15-glider@google.com> Subject: [PATCH v5 14/44] mm: kmsan: maintain KMSAN metadata for page operations From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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() v3: -- use PAGE_SHIFT in kmsan_ioremap_page_range() v4: -- change sizeof(type) to sizeof(*ptr) -- replace occurrences of |var| with @var -- swap mm: and kmsan: in the subject -- drop __no_sanitize_memory from clear_page() v5: -- do not export KMSAN hooks that are not called from modules -- use modern style for-loops -- simplify clear_page() instrumentation as suggested by Marco Elver -- move forward declaration of `struct page` in kmsan.h to this patch Link: https://linux-review.googlesource.com/id/I6d4f53a0e7eab46fa29f0348f30= 95d9f2e326850 --- arch/x86/include/asm/page_64.h | 7 ++ arch/x86/mm/ioremap.c | 3 + include/linux/highmem.h | 3 + include/linux/kmsan.h | 125 +++++++++++++++++++++++++++++++++ mm/internal.h | 6 ++ mm/kmsan/hooks.c | 85 ++++++++++++++++++++++ mm/kmsan/shadow.c | 113 +++++++++++++++++++++++++++++ mm/memory.c | 2 + mm/page_alloc.c | 11 +++ mm/vmalloc.c | 20 +++++- 10 files changed, 373 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h index baa70451b8df5..198e03e59ca19 100644 --- a/arch/x86/include/asm/page_64.h +++ b/arch/x86/include/asm/page_64.h @@ -8,6 +8,8 @@ #include #include =20 +#include + /* duplicated to the one in bootmem.h */ extern unsigned long max_pfn; extern unsigned long phys_base; @@ -47,6 +49,11 @@ void clear_page_erms(void *page); =20 static inline void clear_page(void *page) { + /* + * Clean up KMSAN metadata for the page being cleared. The assembly call + * below clobbers @page, so we perform unpoisoning before it. + */ + kmsan_unpoison_memory(page, PAGE_SIZE); alternative_call_2(clear_page_orig, clear_page_rep, X86_FEATURE_REP_GOOD, clear_page_erms, X86_FEATURE_ERMS, diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 1ad0228f8ceb9..78c5bc654cff5 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -17,6 +17,7 @@ #include #include #include +#include =20 #include #include @@ -479,6 +480,8 @@ 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 25679035ca283..e9912da5441b4 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -311,6 +312,7 @@ 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); } @@ -326,6 +328,7 @@ 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 e578c9627b641..699fe4f5b3bee 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -14,6 +14,8 @@ #include #include =20 +struct page; + #ifdef CONFIG_KMSAN =20 /* These constants are defined in the MSan LLVM instrumentation pass. */ @@ -39,6 +41,129 @@ 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 785409805ed79..fd7247a2367ed 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -847,8 +847,14 @@ 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..2624b4ea3d8ef 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -26,6 +26,91 @@ * 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)); +} + +/* + * 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 nr; + + if (!kmsan_enabled || kmsan_in_runtime()) + return; + + nr =3D (end - start) / PAGE_SIZE; + kmsan_enter_runtime(); + for (int 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(); +} + +void kmsan_iounmap_page_range(unsigned long start, unsigned long end) +{ + unsigned long v_shadow, v_origin; + struct page *shadow, *origin; + int 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 (int i =3D 0; i < nr; + i++, v_shadow +=3D PAGE_SIZE, v_origin +=3D PAGE_SIZE) { + 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(); +} + /* 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 acc5279acc3be..8c81a059beea6 100644 --- a/mm/kmsan/shadow.c +++ b/mm/kmsan/shadow.c @@ -145,3 +145,116 @@ void *kmsan_get_metadata(void *address, bool is_origi= n) =20 return (is_origin ? origin_ptr_for(page) : shadow_ptr_for(page)) + off; } + +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; + + 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 (int 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, 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(*s_pages), GFP_KERNEL); + o_pages =3D kcalloc(nr, sizeof(*o_pages), GFP_KERNEL); + if (!s_pages || !o_pages) + goto ret; + for (int 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 4ba73f5aa8bb7..6cc35d2cae8fd 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -52,6 +52,7 @@ #include #include #include +#include #include #include #include @@ -3128,6 +3129,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) delayacct_wpcopy_end(); 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 e5486d47406e8..d488dab76a6e8 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -1398,6 +1399,7 @@ 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) { /* @@ -3817,6 +3819,14 @@ 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, @@ -5535,6 +5545,7 @@ 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 dd6cdb2011953..68b656e0125c9 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -320,6 +320,9 @@ 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 @@ -416,7 +419,7 @@ 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; @@ -438,6 +441,12 @@ 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 @@ -575,7 +584,7 @@ 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; @@ -601,6 +610,13 @@ 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 455AFECAAA3 for ; Fri, 26 Aug 2022 15:10:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243971AbiHZPKt (ORCPT ); Fri, 26 Aug 2022 11:10:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245420AbiHZPKB (ORCPT ); Fri, 26 Aug 2022 11:10:01 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4EE7BDDAB2 for ; Fri, 26 Aug 2022 08:08:56 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-3363b1dffa0so29064487b3.23 for ; Fri, 26 Aug 2022 08:08:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=jx2yh37l5SDq2Q8QSIum21pACdE/sm5g4yjUaLUM63Q=; b=YwocNvFxNg+yRyYunyC8K2i0xvtr8YUlMRSXD4KB07qL6OVAVJoi69FVpTqeb6vo98 HNk/rkY+3aMZsuK1uxh+Akq9TcZkV7+UoG9UsOjRo11a/ebkyHu3Zk6ZybTqbnEICNl6 fVKoim3Gbw01E9ari0gpTSeEb1JS1RrQj9AECprq43H/JBol2bhhdu4xkoVyjXPE9+Ze 8ecJmXHBW0h1jwcuB7WCNu3ewzYMljdqqcbJK9oNsyWlgppHytBzzquDRDlGLBrz1LbR 1srEjiZAt2vaWQ/YMD9BNRcRUdlTr4PzP3ErRactmJa3ktJHlpH5z9Y33Q29N2lW/xGz lxzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=jx2yh37l5SDq2Q8QSIum21pACdE/sm5g4yjUaLUM63Q=; b=AXVCVSds/aTyyV31L1aWxcr2uIZ27KF1k2xR9CLuuHDyTYFcJakoSAQd309YNDZYSQ YoRZJBgp/cKYXgcVV3/iBNm4ITOpm/Z3BlVnPEa/uJtb+PuMWTtiZKJHXwyyyafitCMn aD7gXbtdMAg8HMojb36/Jgvxs4fJNLmSnEWf5tMbIJWYE8QKzBgRFMkqwv1mG6JgwHJ+ Y+uqc9IN6LRDOW8Gg0kCM2mPuJRBOCSan+zfZVmOB3hBfTg1BHNpqDA+mNxpCOo84xMP Lr6D9zz5XkPsqhn7BBbAK0vxTqLP6wFaSSd86Sc/vjZcpjREjtiC5hsYjVsU4XneuOL8 JiSA== X-Gm-Message-State: ACgBeo0kkbr6a2p30hCxG1eKcJa321a2f4zTXDA4xRMdAZGeHCot1i4O 5/vQYr6C+x3Q4q+6rHABURCf8FU3VTM= X-Google-Smtp-Source: AA6agR603nVbq19tqyU4+Jy5vddr/H1MZ8Z1v7IqPxKbCCNuQvmAeaYyVDn51ytxXs9PxCixOvP5yDsDceQ= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a81:710a:0:b0:33d:c742:4a20 with SMTP id m10-20020a81710a000000b0033dc7424a20mr69884ywc.343.1661526534913; Fri, 26 Aug 2022 08:08:54 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:38 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-16-glider@google.com> Subject: [PATCH v5 15/44] mm: kmsan: call KMSAN hooks from SLUB code From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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. In addition, we apply __no_kmsan_checks to get_freepointer_safe() to suppress reports when accessing freelist pointers that reside in freed objects. Signed-off-by: Alexander Potapenko Reviewed-by: Marco Elver --- v2: -- move the implementation of SLUB hooks here v4: -- change sizeof(type) to sizeof(*ptr) -- swap mm: and kmsan: in the subject -- get rid of kmsan_init(), replace it with __no_kmsan_checks v5: -- do not export KMSAN hooks that are not called from modules -- drop an unnecessary whitespace change Link: https://linux-review.googlesource.com/id/I6954b386c5c5d7f99f48bb6cbcc= 74b75136ce86e --- include/linux/kmsan.h | 57 ++++++++++++++++++++++++++++++++ mm/kmsan/hooks.c | 76 +++++++++++++++++++++++++++++++++++++++++++ mm/slab.h | 1 + mm/slub.c | 17 ++++++++++ 4 files changed, 151 insertions(+) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index 699fe4f5b3bee..fd76cea338878 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -15,6 +15,7 @@ #include =20 struct page; +struct kmem_cache; =20 #ifdef CONFIG_KMSAN =20 @@ -72,6 +73,44 @@ 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. @@ -138,6 +177,24 @@ 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 2624b4ea3d8ef..519a7a1dcb4aa 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -26,6 +26,82 @@ * 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(); +} + +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(); +} + +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(); +} + +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(); +} + 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 4ec82bec15ecd..9d0afd2985df7 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -729,6 +729,7 @@ 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 862dbd9af4f52..2c323d83d0526 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -359,6 +360,17 @@ static void prefetch_freepointer(const struct kmem_cac= he *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, we apply __no_kmsan_checks to ensure that + * get_freepointer_safe() returns initialized memory. + */ +__no_kmsan_checks static inline void *get_freepointer_safe(struct kmem_cache *s, void *objec= t) { unsigned long freepointer_addr; @@ -1709,6 +1721,7 @@ 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 @@ -1716,12 +1729,14 @@ 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 @@ -5915,6 +5930,7 @@ 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 @@ -6016,6 +6032,7 @@ 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(*al)); return 0; } =20 --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 1709CECAAA3 for ; Fri, 26 Aug 2022 15:11:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245608AbiHZPLb (ORCPT ); Fri, 26 Aug 2022 11:11:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245631AbiHZPKU (ORCPT ); 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Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , kasan-dev@googlegroups.com, 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 v4: -- change sizeof(type) to sizeof(*ptr) v5: -- do not export KMSAN hooks that are not called from modules -- minor comment fix Link: https://linux-review.googlesource.com/id/I0f41c3a1c7d66f7e14aabcfdfc7= c69addb945805 --- include/linux/kmsan.h | 21 +++++++++++++++++++++ kernel/exit.c | 2 ++ kernel/fork.c | 2 ++ mm/kmsan/core.c | 10 ++++++++++ mm/kmsan/hooks.c | 17 +++++++++++++++++ mm/kmsan/kmsan.h | 2 ++ 6 files changed, 54 insertions(+) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index fd76cea338878..5ec056380a43b 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -16,6 +16,7 @@ =20 struct page; struct kmem_cache; +struct task_struct; =20 #ifdef CONFIG_KMSAN =20 @@ -42,6 +43,18 @@ struct kmsan_ctx { bool allow_reporting; }; =20 +/** + * 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(). @@ -163,6 +176,14 @@ 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 84021b24f79e3..f5d620c315662 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -60,6 +60,7 @@ #include #include #include +#include #include #include #include @@ -741,6 +742,7 @@ void __noreturn do_exit(long code) WARN_ON(tsk->plug); =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 90c85b17bf698..7cf3eea01ceef 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include #include @@ -1026,6 +1027,7 @@ static struct task_struct *dup_task_struct(struct tas= k_struct *orig, int node) tsk->worker_private =3D NULL; =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 a5dec6e62b4ef..a640e0cccbb64 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; + struct thread_info *info =3D current_thread_info(); + + __memset(ctx, 0, sizeof(*ctx)); + ctx->allow_reporting =3D true; + kmsan_internal_unpoison_memory(info, sizeof(*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 519a7a1dcb4aa..4ab8c629acd0c 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -26,6 +26,23 @@ * 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(); +} + +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; +} + 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 6b9deee3b7f32..04954b83c5d65 100644 --- a/mm/kmsan/kmsan.h +++ b/mm/kmsan/kmsan.h @@ -179,6 +179,8 @@ 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 31BC6ECAAD4 for ; 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Fri, 26 Aug 2022 08:09:00 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:40 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-18-glider@google.com> Subject: [PATCH v5 17/44] init: kmsan: call KMSAN initialization routines From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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) v4: -- change sizeof(type) to sizeof(*ptr) -- replace occurrences of |var| with @var -- swap init: and kmsan: in the subject v5: -- address Marco Elver's comments -- don't export initialization routines -- use modern style for-loops -- better name for struct page_pair -- delete duplicate function prototypes Link: https://linux-review.googlesource.com/id/I7bc53706141275914326df23458= 81ffe0cdd16bd --- include/linux/kmsan.h | 36 +++++++ init/main.c | 3 + mm/kmsan/Makefile | 3 +- mm/kmsan/init.c | 235 ++++++++++++++++++++++++++++++++++++++++++ mm/kmsan/kmsan.h | 3 + mm/kmsan/shadow.c | 34 ++++++ mm/page_alloc.c | 4 + 7 files changed, 317 insertions(+), 1 deletion(-) create mode 100644 mm/kmsan/init.c diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index 5ec056380a43b..f056ba8a7a551 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -55,6 +55,28 @@ 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_alloc_page() - Notify KMSAN about an alloc_pages() call. * @page: struct page pointer returned by alloc_pages(). @@ -176,6 +198,20 @@ 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 91642a4e69be6..f8ca3ad78fbcd 100644 --- a/init/main.c +++ b/init/main.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include #include @@ -836,6 +837,7 @@ 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(); @@ -853,6 +855,7 @@ 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_RANDOMIZE_KSTACK_OFFSET diff --git a/mm/kmsan/Makefile b/mm/kmsan/Makefile index 550ad8625e4f9..401acb1a491ce 100644 --- a/mm/kmsan/Makefile +++ b/mm/kmsan/Makefile @@ -3,7 +3,7 @@ # Makefile for KernelMemorySanitizer (KMSAN). # # -obj-y :=3D core.o instrumentation.o hooks.o report.o shadow.o +obj-y :=3D core.o instrumentation.o init.o hooks.o report.o shadow.o =20 KMSAN_SANITIZE :=3D n KCOV_INSTRUMENT :=3D n @@ -18,6 +18,7 @@ CFLAGS_REMOVE.o =3D $(CC_FLAGS_FTRACE) =20 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..7fb794242fad0 --- /dev/null +++ b/mm/kmsan/init.c @@ -0,0 +1,235 @@ +// 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; + + 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 (int 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; + u64 loop; + int nid; + + for_each_reserved_mem_range(loop, &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 (int 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); +} + +struct metadata_page_pair { + struct page *shadow, *origin; +}; +static struct metadata_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; +}; + +static 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(tmp)); +} + +/* + * 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) +{ + /* + * 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 (int 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; +} diff --git a/mm/kmsan/kmsan.h b/mm/kmsan/kmsan.h index 04954b83c5d65..e064b4601af9d 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, @@ -186,6 +187,8 @@ void kmsan_internal_check_memory(void *addr, size_t siz= e, const void *user_addr, int reason); =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 /* * kmsan_internal_is_module_addr() and kmsan_internal_is_vmalloc_addr() are diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c index 8c81a059beea6..6e90a806a7045 100644 --- a/mm/kmsan/shadow.c +++ b/mm/kmsan/shadow.c @@ -258,3 +258,37 @@ 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 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 (u64 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) +{ + for (int 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 d488dab76a6e8..b28093e3bb42a 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1806,6 +1806,10 @@ void __init memblock_free_pages(struct page *page, u= nsigned 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 18788ECAAD4 for ; Fri, 26 Aug 2022 15:12:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343704AbiHZPMO (ORCPT ); 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Fri, 26 Aug 2022 08:09:03 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:41 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-19-glider@google.com> Subject: [PATCH v5 18/44] instrumented.h: add KMSAN support From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 Reviewed-by: Marco Elver --- v2: -- move implementation of kmsan_copy_to_user() here v5: -- simplify kmsan_copy_to_user() -- provide instrument_get_user() and instrument_put_user() Link: https://linux-review.googlesource.com/id/I43e93b9c02709e6be8d222342f1= b044ac8bdbaaf --- include/linux/instrumented.h | 17 +++++++++++++++- include/linux/kmsan-checks.h | 19 ++++++++++++++++++ mm/kmsan/hooks.c | 38 ++++++++++++++++++++++++++++++++++++ 3 files changed, 73 insertions(+), 1 deletion(-) diff --git a/include/linux/instrumented.h b/include/linux/instrumented.h index ee8f7d17d34f5..5f0525d95026a 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 +153,19 @@ 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 +#define instrument_get_user(to) \ +({ \ + u64 __tmp =3D (u64)(to); \ + kmsan_unpoison_memory(&__tmp, sizeof(__tmp)); \ + to =3D __tmp; \ +}) + +#define instrument_put_user(from, ptr, size) \ +({ \ + kmsan_copy_to_user(ptr, &from, sizeof(from), 0); \ +}) + #endif /* _LINUX_INSTRUMENTED_H */ diff --git a/include/linux/kmsan-checks.h b/include/linux/kmsan-checks.h index a6522a0c28df9..c4cae333deec5 100644 --- a/include/linux/kmsan-checks.h +++ b/include/linux/kmsan-checks.h @@ -46,6 +46,21 @@ 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 static inline void kmsan_poison_memory(const void *address, size_t size, @@ -58,6 +73,10 @@ static inline void kmsan_unpoison_memory(const void *add= ress, 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 4ab8c629acd0c..a8a03f079a8a5 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -204,6 +204,44 @@ void kmsan_iounmap_page_range(unsigned long start, uns= igned long end) kmsan_leave_runtime(); } =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); + } else { + /* 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 5D778ECAAD4 for ; Fri, 26 Aug 2022 15:12:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245678AbiHZPMo (ORCPT ); Fri, 26 Aug 2022 11:12:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34280 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244026AbiHZPKz (ORCPT ); Fri, 26 Aug 2022 11:10:55 -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 7C499DEB45 for ; Fri, 26 Aug 2022 08:09:12 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id sc3-20020a1709078a0300b0073d77f805b3so731691ejc.22 for ; Fri, 26 Aug 2022 08:09:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=9AAV0khTKYQgqo5/UGS2nmhcIjrHMBeghL7l+ejLApU=; b=sDB5PJpJBZJ8zJUYHqSaroGLwunSs5Rwaz9QmpK5RO8+mlf1nYQAGNhjMXl1m0oFZH vzMQVlJHXNGU9aieZuBV0ihX2Xs7GeZCanFYLMBLdccTjtufIvPj0/C/g25QTIwI6/Qp sReL0ZmVrFu7c6GRkrze5jnIbC0eHcDyF/YHGMdyIlE3tPtruebYgAGRN7/qwGwqWIG0 d7O6U7dzRkmvp5N9Pl4k3vT+ZH5Z9JXhcKEWunCg7MMWVXl8aGl5D3s28uVHexHgHJDm JLeAgRz2XBzUtSevuOYUNl/dsbWhlT4VB5dIjKptqOcveXztv31OO3ARcYOVZyimZv3m XuFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=9AAV0khTKYQgqo5/UGS2nmhcIjrHMBeghL7l+ejLApU=; b=UiLuob3j4ASArGdGEcE7T22NIztV3iOfpPJfUi5D3u2cuJtM4EmoQmcqJA5dPlREa7 Yt8h4a/qFXQ6sIRGgt4GSFu6crUUlPao/WhR3PNVDDnqiuj4OY5VDnKvfidhCmnc3+Pu kAxGyicjpNK+sM6kAeNo/rYCU78z5RKuAvjcOCwkxynCU/wilWBd7knk4TXUa3YcvdHq fW3V4Izfqkc2ANzYzCcl5zlXvx9pbTZjNx/OrBBi7IhYwn+wBTZHVhzfgZCopCuucg0z ig1bNE4lyXdk6ShgjQdLrNQeViD80zmOvBHMt3TLZphTGmy0rN9GUQLD0nDxxcc2LbHx woSA== X-Gm-Message-State: ACgBeo2GstpkX5VhMmK+c96G8QMvaUMUk+ujNUav5QBx0DAwlNcMv728 i6oJl8IPyOFAyGy7Bc2t+HS88g1JW4w= X-Google-Smtp-Source: AA6agR7OB7JfBU0FR/Gx7VVFS0BYXkDkX/D+5e1f7tZDKGDtu48HBg9ANVBecrhroNJG7bsthdjAB8Rc34M= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a17:906:8a77:b0:73d:deef:8f76 with SMTP id hy23-20020a1709068a7700b0073ddeef8f76mr3332086ejc.765.1661526545890; Fri, 26 Aug 2022 08:09:05 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:42 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-20-glider@google.com> Subject: [PATCH v5 19/44] kmsan: unpoison @tlb in arch_tlb_gather_mmu() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 an optimization 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 Acked-by: Marco Elver --- v5: -- updated description as suggested by Marco Elver 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 a71924bd38c0d..add4244e5790d 100644 --- a/mm/mmu_gather.c +++ b/mm/mmu_gather.c @@ -1,6 +1,7 @@ #include #include #include +#include #include #include #include @@ -265,6 +266,15 @@ 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 779C8ECAAA3 for ; Fri, 26 Aug 2022 15:12:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245559AbiHZPMh (ORCPT ); Fri, 26 Aug 2022 11:12:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245438AbiHZPKr (ORCPT ); Fri, 26 Aug 2022 11:10:47 -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 6C68ADEA73 for ; Fri, 26 Aug 2022 08:09:09 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id f18-20020a056402355200b00446c8d2ed50so1220898edd.18 for ; Fri, 26 Aug 2022 08:09:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=sAAv4rjcKBcVdRkEmlFE/2pa6fVQ+FymuVP5r3ZkSlI=; b=JZiG5Re4MF+VCa2xcEOtoGIN0T2/OlhDseNXFK0iQ1PnqQdTbI1JZrkp7lVyg8+XXy 3FX58aOp3yEhQ69BL9KLP1xsx5YJIe9+zppmM6QMfAhSuxAKThSHgjQM2yycPHihDuKz i2djpfTU43h2g5u3Lr7aPVAqaJIecBrr7/zGlgzSAGfdlt6KxN6oVSMfJ2omoi6N/bK4 GRhnLyqkHBfxBRxMrlZ83fqspSPBqI2I6ldHAHjwHJMOXx3wWPO3DfQ80yGF5CLrbpfN 7wncFTD4b9cCQe70WIerWDhBUOJbuexSLBDBhL5Axyzz/siEoiRyAYSkCi88l1QWaf/L BH0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=sAAv4rjcKBcVdRkEmlFE/2pa6fVQ+FymuVP5r3ZkSlI=; b=s5WXW3nUhdZIP/9PJ1i0qUhDYy0yIkdlHNnFMLYT4QP3NJJMjWHMS3H21AIhnoOaON v5FOlMK15fbMvj+dQRNeU7a/FZJsyEcREqPfDldVrn8+zGfupfjMsKjXQsQdHlFzcqFa J1TvSScMctji4Xux5ovnKw8u1Z54pj0bjbUcyCY19wBp1lIsVPORid/VH20EJwLT0VVA kpwBHRScdhZ4dXlfYLyVRURMNj2vCLns6/lqbX9bwyxpM0zPGzS+dAC9N/yX3yIWTKgA tkwoPpXr2X7hjtIHDICKAztHtZLFO+SRj8rGhUvXh9aXRVsAWLlgefwYSLA2WVpTeKge 9EkQ== X-Gm-Message-State: ACgBeo113nL2hyUfdIZNyRrYzj3aFAsc7e+z4KKuiAWPMbT0F4+bNAHe FLXl0K3IYYWdBBJtcxAtdH9c1AIysww= X-Google-Smtp-Source: AA6agR7I8UjZBgTpe1NFCsD09x2YoQcBDBFrSyqklOpQRZZDZsEGkSDDS6+A5L7hb/nYEuWrc359HGbAT9Q= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:894:b0:447:fe25:15cf with SMTP id e20-20020a056402089400b00447fe2515cfmr1613274edy.404.1661526548777; Fri, 26 Aug 2022 08:09:08 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:43 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-21-glider@google.com> Subject: [PATCH v5 20/44] kmsan: add iomap support From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 --- v4: -- switch from __no_sanitize_memory (which now means "no KMSAN instrumentation") to __no_kmsan_checks (i.e. "unpoison everything") Link: https://linux-review.googlesource.com/id/I45527599f09090aca046dfe1a26= df453adab100d --- lib/iomap.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/lib/iomap.c b/lib/iomap.c index fbaa3e8f19d6c..4f8b31baa5752 100644 --- a/lib/iomap.c +++ b/lib/iomap.c @@ -6,6 +6,7 @@ */ #include #include +#include =20 #include =20 @@ -70,26 +71,35 @@ static void bad_io_access(unsigned long port, const cha= r *access) #define mmio_read64be(addr) swab64(readq(addr)) #endif =20 +/* + * Here and below, we apply __no_kmsan_checks to functions reading data fr= om + * hardware, to ensure that KMSAN marks their return values as initialized. + */ +__no_kmsan_checks unsigned int ioread8(const void __iomem *addr) { IO_COND(addr, return inb(port), return readb(addr)); return 0xff; } +__no_kmsan_checks unsigned int ioread16(const void __iomem *addr) { IO_COND(addr, return inw(port), return readw(addr)); return 0xffff; } +__no_kmsan_checks unsigned int ioread16be(const void __iomem *addr) { IO_COND(addr, return pio_read16be(port), return mmio_read16be(addr)); return 0xffff; } +__no_kmsan_checks unsigned int ioread32(const void __iomem *addr) { IO_COND(addr, return inl(port), return readl(addr)); return 0xffffffff; } +__no_kmsan_checks unsigned int ioread32be(const void __iomem *addr) { IO_COND(addr, return pio_read32be(port), return mmio_read32be(addr)); @@ -142,18 +152,21 @@ static u64 pio_read64be_hi_lo(unsigned long port) return lo | (hi << 32); } =20 +__no_kmsan_checks u64 ioread64_lo_hi(const void __iomem *addr) { IO_COND(addr, return pio_read64_lo_hi(port), return readq(addr)); return 0xffffffffffffffffULL; } =20 +__no_kmsan_checks u64 ioread64_hi_lo(const void __iomem *addr) { IO_COND(addr, return pio_read64_hi_lo(port), return readq(addr)); return 0xffffffffffffffffULL; } =20 +__no_kmsan_checks u64 ioread64be_lo_hi(const void __iomem *addr) { IO_COND(addr, return pio_read64be_lo_hi(port), @@ -161,6 +174,7 @@ u64 ioread64be_lo_hi(const void __iomem *addr) return 0xffffffffffffffffULL; } =20 +__no_kmsan_checks u64 ioread64be_hi_lo(const void __iomem *addr) { IO_COND(addr, return pio_read64be_hi_lo(port), @@ -188,22 +202,32 @@ 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 +263,32 @@ 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 +360,20 @@ 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 +381,20 @@ 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 BAC0BECAAD4 for ; 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Fri, 26 Aug 2022 08:09:11 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:44 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-22-glider@google.com> Subject: [PATCH v5 21/44] Input: libps2: mark data received in __ps2_command() as initialized From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 0C4D9ECAAA3 for ; Fri, 26 Aug 2022 15:13:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343628AbiHZPNI (ORCPT ); Fri, 26 Aug 2022 11:13:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243549AbiHZPMD (ORCPT ); Fri, 26 Aug 2022 11:12:03 -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 211A4DEB6E for ; Fri, 26 Aug 2022 08:09:20 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id hb37-20020a170907162500b0073d7f7fbbbfso725041ejc.17 for ; Fri, 26 Aug 2022 08:09:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=76jHGgwozZvM48bVgyafH0ePqqgPygQeeBv9QE8zFSs=; b=Ez/lNwvAaDDeJuJMLhCTbPEpOPlHhfNIq7VyjE0qAVyZCRontZv0oB0LtGJ+nv4bwC gZw/mTwPTBWyA0dCxVGdhKH7XEOHdENq7Cv0XhQdf86eksUUxOa2+VWsVcz6rEA4dWpu Zvs62QVT+xB2cN1avkjLXHEoEa+e1ekxcYkU9ofidPy0VrkaWYbMd4GmDWtb/KlvsLO2 yXZ6UmXxmwAic31Rzt9UwrAuioHtXeVlWsWj3qGlJA79GCkFWZNr2tEMTQpyVXsI1d7b 0KcOCYL7oQy7CjEb6pflswFigH5TXa8Rfml+4QXtapWs+MN75E6ySnIaQBQTkmU2kvfY TSxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=76jHGgwozZvM48bVgyafH0ePqqgPygQeeBv9QE8zFSs=; b=Fw3SwRcBD8OwAJnR35YbFD3KNdrs3dL1f2Ukm//tOzPBVyAIGjHhXVjKmn1Q1VKdRX i557yblngNXOX1Hu+lprW+GfcXEbM8RaXjLaxHwOHcOT1unV6XDjh6wXbkq3LzFOaYfp SWq1fI84amhYRGhjykGx4LlDyetotHrDn5sk8Y3eh7JNJFoaJzNwmUl0V2/HgmS0Lneu oy3M62kae4MBKuApC9EpAUJb0VFUVI3wSj9lOw+ByQsPnRhXrriojnGUwEkcQoZvh86t 1R4lXXf+5B5fo/FErQ1b153IR1kF1V0RMgg+LgUwBqUP7FiUhN/tqqKHPVeYmzKuswnp iwEw== X-Gm-Message-State: ACgBeo3zQBh7BIyJ+M4oH8UaxMDHNUQt3/fQvFMK99wYEWbkE55WlUp2 T0zs/uYugKeZoEBEmZRL0M33qoT4cgU= X-Google-Smtp-Source: AA6agR6bf5SCba3ePQHoJhycDuv14GdKQb0ZRH0Sro37EO5apbOGfCrAwn2LLTqoAO1tZW/O5CJdylcsL78= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a17:906:8458:b0:73d:d0e9:4b27 with SMTP id e24-20020a170906845800b0073dd0e94b27mr5257444ejy.766.1661526554281; Fri, 26 Aug 2022 08:09:14 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:45 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-23-glider@google.com> Subject: [PATCH v5 22/44] dma: kmsan: unpoison DMA mappings From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 v4: -- swap dma: and kmsan: int the subject v5: -- do not export KMSAN hooks that are not called from modules Link: https://linux-review.googlesource.com/id/Ia162dc4c5a92e74d4686c1be32a= 4dfeffc5c32cd --- include/linux/kmsan.h | 41 ++++++++++++++++++++++++++++++ kernel/dma/mapping.c | 9 ++++--- mm/kmsan/hooks.c | 59 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 106 insertions(+), 3 deletions(-) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index f056ba8a7a551..c6ae00e327e5e 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 @@ -17,6 +18,7 @@ struct page; struct kmem_cache; struct task_struct; +struct scatterlist; =20 #ifdef CONFIG_KMSAN =20 @@ -196,6 +198,35 @@ 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) @@ -278,6 +309,16 @@ 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 49cbf3e33de71..48dfd11807be2 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 && ents !=3D -EREMOTEIO)) + } else if (WARN_ON_ONCE(ents !=3D -EINVAL && ents !=3D -ENOMEM && + ents !=3D -EIO && ents !=3D -EREMOTEIO)) { return -EIO; + } =20 return ents; } diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index a8a03f079a8a5..41b6b41e6183a 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 @@ -242,6 +244,63 @@ 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; + } +} + +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); +} + /* Functions from kmsan-checks.h follow. */ void kmsan_poison_memory(const void *address, size_t size, gfp_t flags) { --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 57521ECAAD6 for ; Fri, 26 Aug 2022 15:13:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344075AbiHZPM6 (ORCPT ); Fri, 26 Aug 2022 11:12:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245742AbiHZPMA (ORCPT ); Fri, 26 Aug 2022 11:12:00 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C7AFDEB60 for ; Fri, 26 Aug 2022 08:09:17 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-33dbe61eed8so29866577b3.1 for ; Fri, 26 Aug 2022 08:09:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=XOIO6yMrJJaBLCVdiKJxecGrRstBRdkXKAU8JD1YObM=; b=RBRSbeDrL8qGQexUijKhcV3H7NuqN9uz8ZM5rQWAltRN3zhZJP9TKmmIf+p+yKdl6T 3Am09npoAEtHEWxF/Bl4GBV+lvaWA+zyaViXoAoS6FK+zkjAU0V2E1ILS8x3lB5fXtKj 9IHWzkzR0lKD9H/hxXtLbHPszHgU+gNR/ouI3pNZH7yhF0/W+C1cpcyiViY1J1iEBFY8 /rQ0ukMFzwE2rHptS3PuB+v+/gBN3s2bGa1zvZC9PEceq+oso9Jptib23PUbkHkaJtUF ybmLJcK3rBbne7ulW3JpsBkspXiEuaq15wUwrHaqYN3CJnLRo71eoIyBsvku5gZs6p/s mp3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=XOIO6yMrJJaBLCVdiKJxecGrRstBRdkXKAU8JD1YObM=; b=aiRscnRT/ZpEWJD2Y/5DsOImPdDH9iMWW2945UxmhWo5DzTMwaQ+2OWN4NjcLk4aba HtyX7/7dCj4xyjRMvlDSIWM414HkJIevprZ2t7RrFC/wreLYba+xn0VE9hSWJSQqNCFL VpByZZNTXzMabO2e1/ovR+pob6AvE2W3ArLhgoxtXeDiByqvSgvPtWcnddbyZHfCe527 1mtY9tFGZpYqskSz/20EiniRuppWgF1j0tPU2JLNHLgzdy8AqtOyXRI+n5FKWxWD01ku dIs3wo6QsaVOWAxpc5gH0ur1ePzOlWNAbMsXqHRLaIl+/d1N13g+cDo/TaKC16nAHi4U j8+g== X-Gm-Message-State: ACgBeo2WC97jRx69cBq2YSj646Bs668cU2c3gMgkF7NEKB+6vaMFep54 S0vSHCX02D65YlJ+/bFAmYVqDs3lC6s= X-Google-Smtp-Source: AA6agR70pOgUYoVn/e77Ld0R/nqA9LDlWtFjFwsnYYnj15N1nfRnKaSK4PvjO0uXZsTDiRTt9eMo2zal+mA= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a0d:e6cc:0:b0:338:c82b:9520 with SMTP id p195-20020a0de6cc000000b00338c82b9520mr151356ywe.66.1661526556996; Fri, 26 Aug 2022 08:09:16 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:46 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-24-glider@google.com> Subject: [PATCH v5 23/44] virtio: kmsan: check/unpoison scatterlist in vring_map_one_sg() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 --- v4: -- swap virtio: and kmsan: in the subject 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 4620e9d79dde8..a9f06ec5b3c27 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include =20 @@ -352,8 +353,15 @@ 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 CDE68ECAAA3 for ; Fri, 26 Aug 2022 15:13:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343746AbiHZPNO (ORCPT ); Fri, 26 Aug 2022 11:13:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243925AbiHZPMD (ORCPT ); Fri, 26 Aug 2022 11:12:03 -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 4820EDCFEA for ; Fri, 26 Aug 2022 08:09:21 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id h17-20020a05640250d100b00446d1825c9fso1231390edb.14 for ; Fri, 26 Aug 2022 08:09:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=PLcPoxyp1Xs3M8CttNEhz4gH6ZMFq0yiGHMdwreSHbw=; b=eh86TxxX8CwLNIBltPXsm5933LECqY2eAlL/5pBl4nWbjLT9wwFJMOBUyie0dUx/gK N82SKr30PljWUvEhhV3/fUE7T4qgCesvwEM4KVHBlRwHJfYrj27gozIMUwRuSF5xcEdQ H894CHa15jZo0p4ubi/COw4OT1+/6PqIggnVwzZ+BFxk13rWrsC3JvKzP9SXV8kNUkWw FrowsNGwL8zWTGrIAcdj6cj5ZG+bP7h4Z/52tgm2GPymsQ498t6GXSFQ1gYV+/OZFD23 v1gAArrhOq4so6cVSxA30W0GuwEXdIdz3gBKSYzqaYbpXdCyauICiavckkCPIg9Kvzky 3pOw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=PLcPoxyp1Xs3M8CttNEhz4gH6ZMFq0yiGHMdwreSHbw=; b=aiZSR+5uC0fsKAkVtu2HjEHb8TUHEMpNYcZaDTjtHurvS64i5s52gnpIOtOoFCiGZB B6VP8EIM7I6Exi0UGimkROrRJmC+HyVDVJR3pT3u2EJyt2o1I76sASHQ18OYdWgGR92+ DdY+9eIWaImhc4IwaPcu4LIsRFk3LKGwhXh7Zcjr0iNphXS1eOP2ZAKXIoalcpfdmelO w66izDgbNh799zirJ7EBoitMOb6TQ1FYgOAwMnXEMpUPD3Sj/t35BiIVXVc7LwtnyRhO jB9ZG1kyugSpwRHk/ZN3YbrwOH7PbhbFS8wl+TWSZ7VB2F1S36yBSPSA8O3MsqD1YL8B czlg== X-Gm-Message-State: ACgBeo2CN/79EteEqeS52alAaM0qYtdxTKJtHze/kFILnCJAvxGHUFRG TtTozf5JDslkSfbsX67FI3XN1do+y54= X-Google-Smtp-Source: AA6agR5Si5/g8lHkQ9CsnDZQfnsfIgUA6fce6EFE/ZPTPJJ8orAZDc8GQqAPENSTfPcrOej8JbL/c8L8O08= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:2804:b0:439:83c2:8be2 with SMTP id h4-20020a056402280400b0043983c28be2mr7114308ede.292.1661526559748; Fri, 26 Aug 2022 08:09:19 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:47 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-25-glider@google.com> Subject: [PATCH v5 24/44] kmsan: handle memory sent to/from USB From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 v5: -- do not export KMSAN hooks that are not called from modules Link: https://linux-review.googlesource.com/id/Ifa67fb72015d4de14c30e971556= f99fc8b2ee506 --- drivers/usb/core/urb.c | 2 ++ include/linux/kmsan.h | 15 +++++++++++++++ mm/kmsan/hooks.c | 16 ++++++++++++++++ 3 files changed, 33 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 c6ae00e327e5e..84dddf3aa5f8b 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -19,6 +19,7 @@ struct page; struct kmem_cache; struct task_struct; struct scatterlist; +struct urb; =20 #ifdef CONFIG_KMSAN =20 @@ -227,6 +228,16 @@ 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) @@ -319,6 +330,10 @@ 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 41b6b41e6183a..58334fa32ff86 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" @@ -244,6 +245,21 @@ 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); +} + static void kmsan_handle_dma_page(const void *addr, size_t size, enum dma_data_direction dir) { --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 561D9ECAAD4 for ; Fri, 26 Aug 2022 15:13:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343798AbiHZPNr (ORCPT ); Fri, 26 Aug 2022 11:13:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35052 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245014AbiHZPM1 (ORCPT ); Fri, 26 Aug 2022 11:12:27 -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 ED790DEB5D for ; Fri, 26 Aug 2022 08:09:26 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id r20-20020a05640251d400b00446e3eee8a1so1242407edd.21 for ; Fri, 26 Aug 2022 08:09:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=BnKMvyT06ziUGsHEJ+YEVg1tx1KzLMz0gVcHVszo8K8=; b=EiVhLZEafaAyrZD6tszEO+TFY0OwioS1rJEC090Ib8NqUc5RrN05qy/vhK9oORIELc q/QX5phZQlclN0vAwmre9pavOoMPSMR6b7/nDdQZXXzMUIiI3CVSylEHitI3THbl54p2 4qw7aI/LSIwMFTpLkQNpGoFPsRI8VBvLcPDhmP9K+AZRW4ddxRhKn6L+7er0aEKIUpsq bMu4phiNih75hkLHoSGS+NneFlparqIZFfB/r7Zkjuxpl6dn28Io0lrtCQeI4wsT5Qmi 1J6Z/uAiwcf/d7OWXeqDUXR7Tj6ogWTRPjMPRiCmUlSHq/K3bRhSzPnBf90OnZ0vFN0L 8vMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=BnKMvyT06ziUGsHEJ+YEVg1tx1KzLMz0gVcHVszo8K8=; b=HLCll9qw+30Kx28+vCBPzUcg/T/zyvKnSsR2mm5+ZwM6VoM6NlR96BXeFcVKHEWjcg oa13Llq547PSUUz33c6xI0JDlnGjG8LYRR7jtq5oKMb3JUy7mtZjvcuU9S+2JtDapAGf 9Dwf4SaLaNDIvaV5Xi+nTIeBNlUJzh5uzebixkciXIaRi/msrsxOuJyUF3XHZO3xIvdy YcggX+lNvw2Yg3IcovCp+C4uWY29Ep+ZJddQWEVL8fbXe1sJuPNShrhc+KyGjSB4nltt PR+1BCn4Y+a4DQdDdScBYtZXOMsDNAzRudERsZFFJLb7GLDB9ty0Dl+zo7vT8Z4LKaGw ak/A== X-Gm-Message-State: ACgBeo1scz6xh4mJOnla+0eosX6X7ikRNX+bflS7BkvCh15kpV8mKrRm W6DE0B7j+/1CZFJHLEboR5XQzq3Qp5g= X-Google-Smtp-Source: AA6agR530TBlVn6mJbY7hmqOW/mIwoixWfGev+K32pLS7qNxq2UBJFhzrDfOIH4huqWlAfhVzxFwU8akYLI= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a17:907:7388:b0:73d:c311:2f3e with SMTP id er8-20020a170907738800b0073dc3112f3emr5671141ejc.158.1661526562331; Fri, 26 Aug 2022 08:09:22 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:48 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-26-glider@google.com> Subject: [PATCH v5 25/44] kmsan: add tests for KMSAN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 v4: -- change sizeof(type) to sizeof(*ptr) -- add test expectations for CONFIG_KMSAN_CHECK_PARAM_RETVAL v5: -- reapply clang-format -- use modern style for-loops -- address Marco Elver's comments Link: https://linux-review.googlesource.com/id/I49c3f59014cc37fd13541c80beb= 0b75a75244650 --- lib/Kconfig.kmsan | 12 + mm/kmsan/Makefile | 4 + mm/kmsan/kmsan_test.c | 552 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 568 insertions(+) create mode 100644 mm/kmsan/kmsan_test.c diff --git a/lib/Kconfig.kmsan b/lib/Kconfig.kmsan index 5b19dbd34d76e..b2489dd6503fa 100644 --- a/lib/Kconfig.kmsan +++ b/lib/Kconfig.kmsan @@ -47,4 +47,16 @@ config KMSAN_CHECK_PARAM_RETVAL may potentially report errors in corner cases when non-instrumented functions call instrumented ones. =20 +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 401acb1a491ce..98eab2856626f 100644 --- a/mm/kmsan/Makefile +++ b/mm/kmsan/Makefile @@ -22,3 +22,7 @@ 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..b68f4334cf184 --- /dev/null +++ b/mm/kmsan/kmsan_test.c @@ -0,0 +1,552 @@ +// 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(*ptr), 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(*ptr), GFP_KERNEL); + memset(ptr, 0, sizeof(*ptr)); + 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(*ptr), 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) +{ +#ifdef CONFIG_KMSAN_CHECK_PARAM_RETVAL + /* + * With eager param/retval checking enabled, KMSAN will report an error + * before the call to two_param_fn(). + */ + EXPECTATION_UNINIT_VALUE_FN(expect, "test_params"); +#else + EXPECTATION_UNINIT_VALUE_FN(expect, "two_param_fn"); +#endif + 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; + + for (int 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; + + kunit_info(test, "pages initialized via vmap (no reports)\n"); + + pages =3D kmalloc_array(npages, sizeof(*pages), GFP_KERNEL); + for (int 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 (int i =3D 0; i < npages; i++) + kmsan_check_memory(page_address(pages[i]), PAGE_SIZE); + + if (vbuf) + vunmap(vbuf); + for (int 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; + 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 (int 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) +{ +#ifdef CONFIG_KMSAN_CHECK_PARAM_RETVAL + /* + * With eager param/retval checking enabled, KMSAN will report an error + * before the call to pr_info(). + */ + EXPECTATION_UNINIT_VALUE_FN(expect, "test_printk"); +#else + EXPECTATION_UNINIT_VALUE_FN(expect, "number"); +#endif + 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 report)\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 report)\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 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); +} + +static int kmsan_suite_init(struct kunit_suite *suite) +{ + /* + * 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 0; +} + +static void kmsan_suite_exit(struct kunit_suite *suite) +{ + for_each_kernel_tracepoint(unregister_tracepoints, NULL); + tracepoint_synchronize_unregister(); +} + +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, + .suite_init =3D kmsan_suite_init, + .suite_exit =3D kmsan_suite_exit, +}; +kunit_test_suites(&kmsan_test_suite); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Alexander Potapenko "); --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 BBB26ECAAD4 for ; Fri, 26 Aug 2022 15:13:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245208AbiHZPNn (ORCPT ); Fri, 26 Aug 2022 11:13:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242796AbiHZPM1 (ORCPT ); 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Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , kasan-dev@googlegroups.com, 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 6f334420f6871..3371d26a0e390 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 80CC7ECAAA3 for ; Fri, 26 Aug 2022 15:13:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344228AbiHZPNy (ORCPT ); Fri, 26 Aug 2022 11:13:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36710 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239844AbiHZPM3 (ORCPT ); Fri, 26 Aug 2022 11:12:29 -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 846FCDF088 for ; Fri, 26 Aug 2022 08:09:28 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id sc3-20020a1709078a0300b0073d77f805b3so732114ejc.22 for ; Fri, 26 Aug 2022 08:09:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=1gFHCXdD1YZhZE1n87Od5kpjEzNiLhH4oD7CKEg8NyA=; b=C36uYdPsFbGg613/pEp7hUDG4/V4Hby9x4YJDjLdSHXRVADGe3qYmz+FhENc9qWMpn 1fHH+6dULxF6nztHlikbu+gl/MQWdeDCP9VB2zmHX7SxVaqPprtH8w7ACXfxBbSDIKlS kWtqNRu27MLLf6vQ4GWLQZltqrIfq9HjjMB2CrQ8XK2g1T2veDcTsdCIa2olLf0K3eB0 rg+ABbqOAL/7dhxwjAOJ4Hp69x9veOEyPpurQPf3/PZhpf9MC+hMgs6YPAy2sAPS4ix/ hldXHsSDQFNMlA9A7JgVHVRI19radrkKrNpF4RzeUo6MiKv+aKuCDRBFbaAp0IFkmn8h cu8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=1gFHCXdD1YZhZE1n87Od5kpjEzNiLhH4oD7CKEg8NyA=; b=OW+X3pc7+gNumAu+8j6p/W1NAQ/Go2Qi15SO8lEGGEOoV/dsY1z9O0WDmIw/T5rF8C QyKM/lrTcYCxKB/hDNQf7eUc+hxcyut7Tr+KLzVbRwMRfVkmGlA5ylUM+LsKGJWiCkJt lev+88OMsW9mWK2TEE+pAK9Epjgz69qxAQUKwj3TPMLKmoD7sg6H0i+0WiJX8doE4Ko8 cn/kLkYkJB3s4ks1Cbg7wdCN4tPlEwNJVWS+5R5vKPaIR14idWHZyuZ3g1Jcy2Vqamhr L7wBOINujLb5B1r1o5abr2ZV5PTpRuQ4gC7ysfBW9qecdU4jhK+P/S0Mo/R2lNKNfbRM vn7w== X-Gm-Message-State: ACgBeo13E2dU44N9fZyhc/laNmZRk9Jw7vQuF4tGeYxeIT/TdAsOsURL EilspTD0sUpmdPuqxRtwd5yBBhW+DCc= X-Google-Smtp-Source: AA6agR4dU1oVd473jtavrnrWb2PmEIjOlLC7x44i18xmbb0FTAubsZR2JzCTs0yhSsAGbXPQw2wAkr5SI/I= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:882:b0:447:e6b9:89db with SMTP id e2-20020a056402088200b00447e6b989dbmr2901305edy.346.1661526567955; Fri, 26 Aug 2022 08:09:27 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:50 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-28-glider@google.com> Subject: [PATCH v5 27/44] crypto: kmsan: disable accelerated configs under KMSAN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 bb427a835e44a..182fb817ebb52 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -319,6 +319,7 @@ 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 @@ -367,11 +368,13 @@ 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 @@ -517,6 +520,7 @@ 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 @@ -525,6 +529,7 @@ 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 @@ -649,6 +654,7 @@ 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 @@ -689,6 +695,7 @@ 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 @@ -748,6 +755,7 @@ config CRYPTO_BLAKE2B config CRYPTO_BLAKE2S_X86 bool "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 @@ -762,6 +770,7 @@ 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, @@ -831,6 +840,7 @@ 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 @@ -920,6 +930,7 @@ 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 @@ -931,6 +942,7 @@ 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 @@ -943,6 +955,7 @@ 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 @@ -1168,6 +1181,7 @@ 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 @@ -1228,6 +1242,7 @@ 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 @@ -1369,6 +1384,7 @@ 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 @@ -1399,6 +1415,7 @@ 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 @@ -1415,6 +1432,7 @@ 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 @@ -1433,6 +1451,7 @@ 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). @@ -1478,6 +1497,7 @@ 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 @@ -1501,6 +1521,7 @@ 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 @@ -1534,6 +1555,7 @@ 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 @@ -1604,6 +1626,7 @@ 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 @@ -1674,6 +1697,7 @@ 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 @@ -1693,6 +1717,7 @@ 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 @@ -1712,6 +1737,7 @@ 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 @@ -1732,6 +1758,7 @@ 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. @@ -1876,6 +1903,7 @@ 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 @@ -1893,6 +1921,7 @@ 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 @@ -1913,6 +1942,7 @@ 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 94c889802566a..2aaf02bfe6f7e 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 7CD53ECAAA3 for ; Fri, 26 Aug 2022 15:14:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244015AbiHZPN6 (ORCPT ); Fri, 26 Aug 2022 11:13:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343787AbiHZPMa (ORCPT ); Fri, 26 Aug 2022 11:12:30 -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 7B137DF093 for ; Fri, 26 Aug 2022 08:09:31 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id w20-20020a05640234d400b00447e6ffefccso1265265edc.0 for ; Fri, 26 Aug 2022 08:09:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=+5QrT5xfdlDeiLaqkJXiB84dUzsqj5PxvneJHk/QPSg=; b=psU325BcC9yCrTgirTaG4c6+Xtt5yEuOoqBDgzPyoh8Hu/P8wcF78qEe5Fv8Uq6mxM 5keARp+YcPeQ8kw2cba6I1H8TcR6qm0KRbaLOkU+IfLk8PtK83FSP/gowyt+6cMWfvxZ fE9laQ1Snqp2aoMqiOY1YPig7tDAMkED/KaWIJ682ZVuc6+uGvL4n3H/HrRhkL0dFAfP qPPg29aXbvpDPvKUJJFkWAZ+F418Tz4/xxZqjZPJP6QnWJRDQgXx2bOBAWB+HjiGP74T HU0Ev+YyOY48tZD9hgwrs4RkUWaxRCmaLSAihTVflh5YMg0/YJxLiIdMMS9B8R/uWWUE aznw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=+5QrT5xfdlDeiLaqkJXiB84dUzsqj5PxvneJHk/QPSg=; b=Z/aPbPORWwAZct2WQX6mam5o4G6hpoH5ViXa+VLHBQg+sexlLFfQVIUHZxTqqWUZkN icFjFnRORb1zSgFUABLiF7DH8ZICKi0gP6sFPZtG71DmW6f6XxNI7vnCqvzi8O/rkDjm JEyntHUu02XzWwWmQPlf0CQHWLdrTfQut0UtAVCkqiJh8r16+oljHVlC3K8C+GKnmnju Xb+18njkewCBRKSXzPhGqtMOcNM1VS/4S/yVEveKH5mF2N5eHrgbbxdTzX+Hyhu8xCCD UGEuSPXjqZTqwsnEHzForrB0EFEEQgBh3od7ivypcLKGHKKlN5ZsUoA+TIpiYUFbVs8V DC1w== X-Gm-Message-State: ACgBeo3pTEiskqfF1mw8Uju3X5sVvEstpaYvabbRFjEYRgaPHhX9m9hZ 0N86hAZIUqfP3Q8iBM3Jt8KtaHZmwAI= X-Google-Smtp-Source: AA6agR64mNuFawO1j56e/34eHqe4IGdV2CngnQTQuYSPV0pxJ0eEBVtcq2c/F1Fd/CUKRPUFcQzSoaSzSas= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:496:b0:443:a5f5:d3b with SMTP id k22-20020a056402049600b00443a5f50d3bmr7388597edv.331.1661526570674; Fri, 26 Aug 2022 08:09:30 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:51 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-29-glider@google.com> Subject: [PATCH v5 28/44] kmsan: disable physical page merging in biovec From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 d7142c4d2fefb..af02b93c1dba5 100644 --- a/block/blk.h +++ b/block/blk.h @@ -88,6 +88,13 @@ 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 7D2D9ECAAD5 for ; Fri, 26 Aug 2022 15:14:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344318AbiHZPOP (ORCPT ); Fri, 26 Aug 2022 11:14:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245408AbiHZPMg (ORCPT ); Fri, 26 Aug 2022 11:12:36 -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 8EDE9DF080 for ; Fri, 26 Aug 2022 08:09:36 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id s3-20020a056402520300b00446f5068565so1236480edd.7 for ; Fri, 26 Aug 2022 08:09:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=ThlNJAw9Kex8KZrskRhHj0vt2sXcunlblCUmHxCmdH0=; b=qQ2U4pH+aEHV3VhL/BG61D7fD+fTTCboEipAha6RdIlQZwkpHT+D6S+zluEN3z1B+q p6KSrVqARRa5621nYeg6EZduZRldgx+r7wiEO2xx4Q1xdyk3NHKRP+n4BtOU+EkTRiBv n9pYohc41L9MNpZ4FFw1iKeBekfif+vSNYJKYp9IPK+WdwoL5Xq+pRz96l2kWYetAuz9 ItAJhGyVh4AlEUo/NPut7UEgT36U97b+onPRJ1+xwb33JHHm9d1XBCaLKaZdeHB78F1o GDrzwrmR2heq2RM/Ijy6NFuNEoHEGLQn9rAcq11k6RQRmGERKya5Rzxx6la0Wnscwu1/ yKKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=ThlNJAw9Kex8KZrskRhHj0vt2sXcunlblCUmHxCmdH0=; b=z3FJPUTAR37Bl0Vi9mScDSh3tu2+iFxD0E5Tks0nAujW8XYuinksn7IjDFzJIdiC2Y ev62G2iWck8Eu/qXJHX6GsrY7YgnBNaJojPviJRobOlQHdoRbISMYCJbDRJElMO66vGW 9VLvG6VX3AGk6fALtvWDtAu5r6YgnIApF3LMGkbuv3qFV+FPUWlXZ4W8HOZcucO9uh3w l/906bM/IDrtRifIYyESP+hd34+3/HsQ6ycdteQ7pH8DoU9/w+q3iZSLWNCryxvY+hgr b9EgcrvsT4aY6XklUY4fSxY0kp7POTbyCNlwpBDfts08vNEnVQLXMY2Iu4HH34kVSzAd ogRg== X-Gm-Message-State: ACgBeo2ffdAwdw5vjUi5zeovcaA3fr8YpLSLgGPsdpl4gHuYR4UdU7XV VNf6/Ry9IU/ucGH0bQMvHS0ArNxSFs4= X-Google-Smtp-Source: AA6agR7P1+orY1RNadpoV0ZNi4BGK9MvXVRSI3uWf43JN88nANc9J/bmowMSnW9dE0hDywQIYKYvs/S52Ck= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a17:906:9b16:b0:73d:af6f:746e with SMTP id eo22-20020a1709069b1600b0073daf6f746emr5932849ejc.32.1661526573448; Fri, 26 Aug 2022 08:09:33 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:52 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-30-glider@google.com> Subject: [PATCH v5 29/44] block: kmsan: skip bio block merging logic for KMSAN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 --- v4: -- swap block: and kmsan: in the subject v5: -- address Marco Elver's comments 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 3d3a2678fea25..106ef14f28c2a 100644 --- a/block/bio.c +++ b/block/bio.c @@ -869,6 +869,8 @@ static inline bool page_is_mergeable(const struct bio_v= ec *bv, *same_page =3D ((vec_end_addr & PAGE_MASK) =3D=3D page_addr); if (*same_page) return true; + else if (IS_ENABLED(CONFIG_KMSAN)) + return false; return (bv->bv_page + bv_end / PAGE_SIZE) =3D=3D (page + off / PAGE_SIZE); } =20 --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 DB833ECAAD5 for ; Fri, 26 Aug 2022 15:14:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245033AbiHZPOs (ORCPT ); Fri, 26 Aug 2022 11:14:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243853AbiHZPNC (ORCPT ); Fri, 26 Aug 2022 11:13:02 -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 42ED6DF0BC for ; Fri, 26 Aug 2022 08:09:38 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id y20-20020a056402359400b00447a871c48fso1248296edc.3 for ; Fri, 26 Aug 2022 08:09:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=RpdJ5KT5GAuxqWidUZuS2M2CiPNp+gZwFhAUBa4xHko=; b=TJz1UTJBESEdKuAr0m8ClDSUAjamVWg2DEv+2WQqCh6Zcxv2oRD55g+O0oye9l40zE VbOvZ3R60SbIN++3IKS2yh90SOwgtqzaCgsQtPATI2d4WJvG5qImDFrX2yJUjrWx8T39 MQQKFjvZ3fA1TYUVsHaA5FR0hdMwNCkK7TJVCIsBqtjkpd/DAEBvNeqI5bfg6Gepswe+ l1jCxIh1lrZEBivplg5yDUBpa6io4UGCJ9ztmW+CUFCm1dTP8QhVkTov1blbHQ6U4xC3 IWO5hCXy6iolpqSQIc2bH9AGoDcxJQSD0LkhoSBkctagTpdhEEFLo7Y5mpIRWVWOlKNE COTA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=RpdJ5KT5GAuxqWidUZuS2M2CiPNp+gZwFhAUBa4xHko=; b=baZQ/MYYXyhOqxWjpnjrSg+w5kBuf0S/Xg6WOoXc2VwTz0mhCGHET9vQhalsEsZOad uMLN6+3bBg7n450OMa21hTa/383xwlTmPIZhkuNdGVwQZGWDTokUDV5qHDC4F5VSnPUA GrY63YUpXB/AscUee4zUSAA7jbLqDTHbpM6c8cr1jGinmY7R7BCSbsJNHUSHmnzGDdPa i4pMvj13vxmjTsMuYfnl9Sqtz0K1OJ9Pnk9OgUZuO78TYGHO1qwjvq9P7/tI5EhAq2tq odwtf83svwqhv+jh2L1aBJ9Bzo3toOssmU3+3EpcpnZ7b9cAP7iIRuqUu6EaK8ymmIJm lqBQ== X-Gm-Message-State: ACgBeo3b/SNtK2dthjJPD6RxufilLCh08f+noawU/13QLTIrsJJE6Aoa XIK6KovoGz4zAxCObtlv3QXOKJVgi1U= X-Google-Smtp-Source: AA6agR5j/r012ARsOS/cLTFyia8pItWWXJH9zXKKE4ubXclVuI6mHNquDQgDo/C5PUvhnsbEwfNt5cuHLt4= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a17:907:2173:b0:73d:c95d:1179 with SMTP id rl19-20020a170907217300b0073dc95d1179mr5669815ejb.89.1661526576513; Fri, 26 Aug 2022 08:09:36 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:53 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-31-glider@google.com> Subject: [PATCH v5 30/44] kcov: kmsan: unpoison area->list in kcov_remote_area_put() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 --- v4: -- change sizeof(type) to sizeof(*ptr) -- swap kcov: and kmsan: in the subject 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 e19c84b02452e..e5cd09fd8a050 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(area->list)); } =20 static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct tas= k_struct *t) --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 D133AECAAD4 for ; Fri, 26 Aug 2022 15:14:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344335AbiHZPOU (ORCPT ); Fri, 26 Aug 2022 11:14:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343829AbiHZPMh (ORCPT ); Fri, 26 Aug 2022 11:12:37 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17045DEA43 for ; Fri, 26 Aug 2022 08:09:41 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-33dc390f26cso29461217b3.9 for ; Fri, 26 Aug 2022 08:09:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=l4zm1sbHMytNqYdogbjGF6C06dm3yrxkJ0CqfKBvE4Y=; b=kOld3GJAUrMocd7PaWFDM8/h7CQ5GhgeZ5vgr609uraCY0vVS54oj+Y6R1RPWTH0by Bq5BNkaD35EK0na6N/L6VeFnDv7KaDTKmgH3r12GWsfNfB14gNvqr5BIJupwb+18QZwN EpJnwctEvW1mQUg89fj3mc+MvJbBuJ+7CVC7Ke4U8VHWQC9tI9ma3K6ekZgZjWQ54T49 jfxIHJNRWKeLLjMm2ThoMvBFZ4QwkjUTc4z2kPoHnmbFzmrfDXm4QKlvn1DyC5ty9ZjW KFjhK6XLeZbpXZp2sTAzuIjtMg/FCCX5xS76W6rdKcowYCqow2Y6Z86qCxoGhCl8H6pW cgBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=l4zm1sbHMytNqYdogbjGF6C06dm3yrxkJ0CqfKBvE4Y=; b=NCP4EW4+nWmeEx7HKiO/A0kzbnCIBKwuJc+KivIf/imZwO1rIWivOYmFHQajx9uPh/ 6MYA9GNw9Of0Mt4MsUe/ofrhF541TM6b/KESo60Osp+cYKZX+XxaY7zBMeII/X4NuyM4 00URyE4pjFDDxLVswXKrOnYBAFmQIRY8FkCbn8Hf5ohz92wvudFq/kzmRkFymrK1Ya9T tlJ0B+5iVByT31UK6oxS8iSx77SBFJYhIt8+Nc/M0IrFgNGlSgdLtEZuFYtUgB3syFxM AQ4YbKqvAc24+hKEu0/trox2csyRmRb5SmwzFMZPrc6u3fSyhMUG/s5N1ZmYMZ6rNxUO QbTg== X-Gm-Message-State: ACgBeo2xmjbkW2o8U5S4ctluEVB0mNuWLkNIM3bDB8aKlVNI6fADRSjO Me1ghqON75vXbI8KbndbBZjbYenHrew= X-Google-Smtp-Source: AA6agR5iGmN+D99SNwa8hGxZHvyED7rP3I7yucWmOXY/88v8RIwEBSFuEsCfj86kvBE/XBr/3trnlWmswJk= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a81:6e06:0:b0:33b:4e1:dd6e with SMTP id j6-20020a816e06000000b0033b04e1dd6emr129882ywc.212.1661526579691; Fri, 26 Aug 2022 08:09:39 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:54 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-32-glider@google.com> Subject: [PATCH v5 31/44] security: kmsan: fix interoperability with auto-initialization From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 b28093e3bb42a..e5eed276ee41d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -936,6 +936,10 @@ 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 bd2aabb2c60f9..2739a6776454e 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 @@ -218,6 +220,7 @@ 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". @@ -230,6 +233,7 @@ 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 14C9EECAAD4 for ; Fri, 26 Aug 2022 15:14:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344403AbiHZPO4 (ORCPT ); Fri, 26 Aug 2022 11:14:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343764AbiHZPNl (ORCPT ); Fri, 26 Aug 2022 11:13:41 -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 445C0DEFD for ; Fri, 26 Aug 2022 08:09:47 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id hb37-20020a170907162500b0073d7f7fbbbfso725540ejc.17 for ; Fri, 26 Aug 2022 08:09:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=wnBRr6RijpcrZwDY4IvPeedZIJ4FbGOivCI4jGGTq68=; b=Q2dLT3h7TWqrdhr9cKJaZHS7iaLiqYTtydJ8WFBafxLMcKO+tWNvB/c1oHlNA44pJ7 /OXz8Sr59WCHZVNiYq5ZO1SudMDbRYsAoPTTGJZwqRehknAE2rlYQmFGjPCW+F59/jA8 4CGBdHbeqGVMdW2YUIUBHbdr0K3ckRBLlyr7LkOy1/yf2HWblMEVwWDcc4r9h7xID/vX XMqQsXajhwumZ46fKGFKaccQ9fQsrPuYa0ruT4rNz0CxhrMmw4c71iIpLPuYx4UZ7eQv mqdpWuXSHPVCrwsBJhHLWeKUt/81aDaMfsn199V9hC6WQQ+JcGqn5dar3vI5lIw7PM1Z VyHQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=wnBRr6RijpcrZwDY4IvPeedZIJ4FbGOivCI4jGGTq68=; b=luXe1OUtwO59MaVgQQ1GzRya3rEJDPbejPrEeScdKIDoBbFa9oPT+JNvtgIhGidMvx T3UqJV1fzet95uzzYrdqTaShphiFqt/v3dpTwxI3x+u3RpgxRlfuDkb8hQJBkMAXWzRA YNykwn1SwT+ZjNTHRIFqldbH6xweMa/2c+QRW2hU5AgCRwuUWjDDtKKr5SehYN0pJ5KC hnPknlD3Y73uM0xHE59V7GqEI92scFbovENSr0IADQ0w+dRTBHbEizHFAZNxQHqIV8qW fBKsAqdoE6TPdOmTByffqIm0+ZuyWbw+naOjAbdeUKpB24rUncluXobPQ9wxqChMmCys xjwA== X-Gm-Message-State: ACgBeo311ehU5ZnRfxG5zHb3RTYpa0OvvodK4Bed98alaqvehCBXh02x Dmnwyl3DLGhRSc/4lcjLOnylmPTmINA= X-Google-Smtp-Source: AA6agR5Cviceae2TWrL6o3zdALqTpxVHsH33a+v7kdsRPAsBV/Ys+W35Cv65k+Ev6zMJg2mViJephdzVroE= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:268d:b0:43d:b9d0:9efc with SMTP id w13-20020a056402268d00b0043db9d09efcmr7340129edd.92.1661526582428; Fri, 26 Aug 2022 08:09:42 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:55 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-33-glider@google.com> Subject: [PATCH v5 32/44] objtool: kmsan: list KMSAN API functions as uaccess-safe From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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. KMSAN API functions are used to update the metadata (shadow/origin pages) for kernel memory accesses. The metadata pages for kernel pointers are also located in the kernel memory, so touching them is not a problem. For userspace pointers, no metadata is allocated. If an API function is supposed to read or modify the metadata, it does so for kernel pointers and ignores userspace pointers. If an API function is supposed to return a pair of metadata pointers for the instrumentation to use (like all __msan_metadata_ptr_for_TYPE_SIZE() functions do), it returns the allocated metadata for kernel pointers and special dummy buffers residing in the kernel memory for userspace pointers. As a result, none of KMSAN API functions perform userspace accesses, but since they might be called from UACCESS regions they use user_access_save/restore(). Signed-off-by: Alexander Potapenko --- v3: -- updated the patch description v4: -- add kmsan_unpoison_entry_regs() Link: https://linux-review.googlesource.com/id/I242bc9816273fecad4ea3d97739= 3784396bb3c35 --- tools/objtool/check.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 91678252a9b67..577dfdca635e8 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1060,6 +1060,26 @@ 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_entry_regs", + "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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 6680AECAAA3 for ; Fri, 26 Aug 2022 15:14:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343622AbiHZPOl (ORCPT ); Fri, 26 Aug 2022 11:14:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343558AbiHZPNB (ORCPT ); Fri, 26 Aug 2022 11:13:01 -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 F19FD2F5 for ; Fri, 26 Aug 2022 08:09:45 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id q32-20020a05640224a000b004462f105fa9so1239895eda.4 for ; Fri, 26 Aug 2022 08:09:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=TL1IO7xzXsHa87B/8VTzh6zaFcPyOOUQBNZupLxKBzY=; b=HmM0VO6gyAfILflJdnMgQCrJGnTi5XVkH3YSfQa6Ep7rg4UjuRksDwsSKfdFWywrKQ X82KrgKGqPOH7W1Y085jaYB8hH48o1UO09SOdX25urL9IS+XrJIM0Ssl/7EKgVgUGuxb suAFkuoPLhsCY3yiCTAbiGImLbwkQ5FdkgDFrYP2s7UE16Wpzs+b87M7ywZwNSRcm9YT cGnqAcNCOOLNxnkJmTHzwJPrKl7dQaDEoIofp21fLLf8UCuU8TSnY933jziAvQ7zwjo3 /ax/hZi6c/lKBcQc7+qabk0byKdenq8IrwbzMmcRBwdyqFxWLtVcbbN3QqtnjPKNbk+n t0fA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=TL1IO7xzXsHa87B/8VTzh6zaFcPyOOUQBNZupLxKBzY=; b=AiRkh3+VKJOzjOCIVJ6lacTjGpiEJvFl2qqjKsLQ40W3bcXH1wz3wou+s7WHL/cvw0 QK8C4PAy8CNfCxDe/h5S6niweTgPwFxuzepwAXXY4fohgqUOuQ3H3OZXzzT0kI3qdMo4 z9bmIH1oas+psDbfaeFtoJFPcsfm65hnorkDmaPM6Dfg7oHZ+R5J0QtVKGL915BOyei7 jzy/KL0nCrwafHcen9am+/fsBW3+KaVJiXzgsK7X0mIeQOXrttgQJkkQFMbDfF4GJXfp h0uHhBVZgNZZemQqkEBR9aQydfHBjaPDmzBCqpS9+kW55lKyb4P9WRKXZT28T+HfOTXh TzYQ== X-Gm-Message-State: ACgBeo0b/2YODm2T/da/WfMWzgRKktAanICqQ3mmuhSJL94FH0rNzewa QTDPtKPmzZItBkdGmlqQY9UYp3FazeQ= X-Google-Smtp-Source: AA6agR76x5AzTzEwn7EdrRuhdUjJW6rIUhqvD9uYbbBW+SigP/bQyvCEvWgW5kLb9e6YBzYDFPgy1GTjMDc= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a50:fe91:0:b0:43d:c97d:1b93 with SMTP id d17-20020a50fe91000000b0043dc97d1b93mr7390732edt.67.1661526585272; Fri, 26 Aug 2022 08:09:45 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:56 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-34-glider@google.com> Subject: [PATCH v5 33/44] x86: kmsan: disable instrumentation of unsupported code From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 v3: -- added a comment to lib/Makefile v5: -- removed a comment belonging to another 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 ffec8bb01ba8c..9860ca5979f8a 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 35ce1a64068b7..3a261abb6d158 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 12f6c4d714cd6..ce4eb7e44e5b8 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -11,6 +11,9 @@ include $(srctree)/lib/vdso/Makefile =20 # Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE :=3D n +KMSAN_SANITIZE_vclock_gettime.o :=3D n +KMSAN_SANITIZE_vgetcpu.o :=3D n + UBSAN_SANITIZE :=3D n KCSAN_SANITIZE :=3D n OBJECT_FILES_NON_STANDARD :=3D y diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index a20a5ebfacd73..ac564c5d7b1f0 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -33,6 +33,8 @@ KASAN_SANITIZE_sev.o :=3D n # With some compiler versions the generated code results in boot hangs, ca= used # by several compilation units. To be safe, disable all instrumentation. KCSAN_SANITIZE :=3D n +KMSAN_SANITIZE_head$(BITS).o :=3D n +KMSAN_SANITIZE_nmi.o :=3D n =20 # If instrumentation of this dir is enabled, boot hangs during first secon= d. # Probably could be more selective here, but note that files related to ir= qs, 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 f8220fd2c169a..39c0700c9955c 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 CFE3CECAAD4 for ; Fri, 26 Aug 2022 15:16:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244280AbiHZPQE (ORCPT ); Fri, 26 Aug 2022 11:16:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244642AbiHZPOM (ORCPT ); Fri, 26 Aug 2022 11:14:12 -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 5A8FF24BDA for ; Fri, 26 Aug 2022 08:09:56 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id he38-20020a1709073da600b0073d98728570so728419ejc.11 for ; Fri, 26 Aug 2022 08:09:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=3xJV8lOEjvc/s3Zvuma5zSeTndu+UAUJOaQAKluuQYo=; b=iowtS53RHlpCL6qU/VWV5GQVG1CF6AM2cb2K8UF+xf9Eri/m9bP/5b0fP/Yv5g71u0 G4xosRyjwnbYFvqXAKPuwh/r0w9aoa69XWRuAOHrIhWmWSx0iV2XmDVoCP0JlE47FuAB nmm0HUugDUAGgo/u5XwfJyioj1O9wMPKtRlUGvvX8gKw+EEmNXhvxQbPL/ZKDRcZQQPf MtPg7V/4IJP2t5P4sgZyKRHmwuOCzbI6xunPoBepArW292PT19a5ne9C4DB1Q+Nr1eTB S6mxBrnLUZM9ZZ8fq3aL2JmDi/WAivgNEzeAkYRHzPgQwniErjEHU3w34yBn1hByADXw pmoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=3xJV8lOEjvc/s3Zvuma5zSeTndu+UAUJOaQAKluuQYo=; b=4xAo+YaCKf4SsAzHpHifrJreBw0yNMEEcOnolbKkCpIm2C6Ox21xXCCjlug3jwQOxx pw5acR220KBO5Wy2JHZr+yjxqEKjCEWMcuRAECg3/dMkpGepo4LQrnQtvdn7XJzgzzC0 B8GmrbBehUSrVlKzN5ihoxIN0PopI5t/XT9ozx92+Ws1HnEvpPhJtlBgNvxUneAUoVKs xt606JQU4GBtF7Tj0HqRj+/967LRXQAk8UeJ3zj6pLRCQWw0cGiLgrY5Sm0kPhH3t1kB Penf3Hh8tlY9c7No7ldbERL/97wawMsrZb56LQi+62mnHQ8sVv6T1E0LE/iKPgdhRac7 5n/g== X-Gm-Message-State: ACgBeo14V2aeQy2yqn6QCBTfVb/MNcRU/bJvSdk7bQx3wtWa8eJ31Yt1 wioSLP8IQmS1wbNJAJXzSZK8oS0L4DQ= X-Google-Smtp-Source: AA6agR7ZtlC3yezkLYO1v2tXY0fliINor4H6Q3eNUkRHGD2H51HnwKZSVDlZC6/hqKT8jj4k53bs2dn79I8= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:3491:b0:446:ea7d:8d9c with SMTP id v17-20020a056402349100b00446ea7d8d9cmr7130674edc.184.1661526588030; Fri, 26 Aug 2022 08:09:48 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:57 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-35-glider@google.com> Subject: [PATCH v5 34/44] x86: kmsan: skip shadow checks in __switch_to() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 Link: https://linux-review.googlesource.com/id/I520c414f52c19f3ea22377a9c57= 0fff0d5943a95 --- 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. v5: -- Replace KMSAN_ENABLE_CHECKS_process_64.o with __no_kmsan_checks 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 1962008fe7437..6b3418bff3261 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 C3CE9ECAAA3 for ; Fri, 26 Aug 2022 15:16:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234500AbiHZPQK (ORCPT ); Fri, 26 Aug 2022 11:16:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35174 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244684AbiHZPON (ORCPT ); Fri, 26 Aug 2022 11:14:13 -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 2166937FB8 for ; Fri, 26 Aug 2022 08:10:00 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id x9-20020a05640226c900b00447e004ea4cso1243407edd.8 for ; Fri, 26 Aug 2022 08:10:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=+OT6SjVSfWjyqzxbCZyABchDUcmsVpvJACt5vGUex24=; b=Z6njr41sW+TrPWrMaWFwC05L0RlOcYNPG3bg02BhPFfdHpKhjWZb3JQSd3EE7bQR4t BLm0gQ80M2u3Pdlj1pDIh1/qXUSrg7ZtmpWtyd9GiSzXUcv17N5l1NutHYYducPw8Nm1 53fip5LebyiAQRD1QGNbSqOqemN8I8dcjPld+gmWIt0k8q85y5Jr57b99LSEVn0lBt+H zdJQxrYdMQVOvNNpr1+RziHtXPGmKyGhGOD17LJ7bJ7AAVD99iIBY1+G52ypCLREDV+F yPwT4hR+BLBGY/xYmzyBjGu/5to6IUIp+jowlZqMWLLM1SmRm2HCrOTVeGnkhu8gk10k xggQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=+OT6SjVSfWjyqzxbCZyABchDUcmsVpvJACt5vGUex24=; b=WRE9xKxaX18jEuJfG572iIvx2cAI1hsD1P4Kfw4J8VZt27hm2+b5ec7FKnJp/sVQrQ BcPR9iKWJ6Bbo1A7aMKnJ7aq6vkpPWfJurPn/mGoZ96C16ATLCLIChkcjgmGRr68rJhH rUPrcXaqITFK1AFKTucZHsnsQUiOxfaj1U9fSMkGh0qBEg2a3dIJE6yMzID7lp3S/Pc4 aUDcRd4AsEkwZda54h7+wDxHWqW2mRF/gE7RPEnVOA5pWp2HiX6Yzo5VMr1FC++fL6Gg YZ9Durz6KlwWqTGE7abvunHqJ6+USDAMUav5sGvjV3asSKvAMCCDD/opV8zawxrdpF/M 0srA== X-Gm-Message-State: ACgBeo1bw0DuMkjwMpIF8T/C7EfBzpcidA35QuR/s65RUhZn+XC27NIa k7M6/blHNYK9ygyD1LFKTZ5Qi2brLTE= X-Google-Smtp-Source: AA6agR4t0eef92ReeAZR+Mrv7r8ag8b4BdV1NIADifSFVxHgYfyFuws8EoWxRalcgwj85FhAMYNvlh2MVzI= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:43c6:b0:43d:79a6:4e32 with SMTP id p6-20020a05640243c600b0043d79a64e32mr6871771edc.281.1661526590665; Fri, 26 Aug 2022 08:09:50 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:58 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-36-glider@google.com> Subject: [PATCH v5 35/44] x86: kmsan: handle open-coded assembly in lib/iomem.c From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 3e2f33fc33de2..e0411a3774d49 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 @@ static void string_memcpy_fromio(void *to, const volatile= void __iomem *from, si n-=3D2; } rep_movs(to, (const void *)from, n); + /* KMSAN must treat values read from devices as initialized. */ + kmsan_unpoison_memory(to, n); } =20 static void string_memcpy_toio(volatile void __iomem *to, const void *from= , size_t n) @@ -44,6 +47,8 @@ static void string_memcpy_toio(volatile void __iomem *to,= const void *from, size 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 96E8DECAAD4 for ; Fri, 26 Aug 2022 15:16:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344116AbiHZPQU (ORCPT ); Fri, 26 Aug 2022 11:16:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344385AbiHZPOl (ORCPT ); Fri, 26 Aug 2022 11:14:41 -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 C2DF375385 for ; Fri, 26 Aug 2022 08:10:02 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id hr32-20020a1709073fa000b00730a39f36ddso715730ejc.5 for ; Fri, 26 Aug 2022 08:10:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=uVzdHqFGYZKd4Qu5GJB2AnYrpVyvjfHfk7LqoEQIkSc=; b=BC1C5JPZyis+Kes9Uu/ankA8YmaxeSDQUFcfBHXb3GZVLgly9+DxFLSdN6o6y7p7/P zVWe/gK4/+LWKxQGuvyhxewoxvI19U5hTqi2IpBvOJg3uq8Ik8xr0FYeUi72cpJlmij9 nf0JKqqIO86qyQ9jue4hqNcyWyObBn/CgX3JM/gkgO+Veqds0ttkLZ3Zg/KDXgiSSHRr oeNOglxG71/shVVy6M1hhBJW9QDDOpd1SAOcY4gcwkPldDcHeI0LxKdaN/3bAC+XERwl jFbWJk+m8LHqzyufpaIWhW/s3AL9MyZZGADD18fKDUyYSRK0x9/0JYGypV1K9dG68puO R0ZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=uVzdHqFGYZKd4Qu5GJB2AnYrpVyvjfHfk7LqoEQIkSc=; b=SSlav8MsRadaguA8I4Z8EBPnWR03kDoTXYy0cN/fznYzHQYFC3acz/OEJbDa3vnKFY JNoS9RHxDX58pu/tnF+3Tkq08uJOcjxL71TAd4BViIIBrjouqMCYsouTtp37S9essNL1 jtEMSu7fM8CPrQtkXsXCClMql+rqciJ/hIagmRW+A8BDQ4DMhCAD9QTdcNvtUfhodEmW xbaz8Lm9kwMYtqDTUDGP+rHN0GOqQSiS4O89WQcVrZTO0t7AjQnr+8QM8DecjilUq56j IiYbXzlmwDjTJWOFjqd4CfFt+gPAcgvuq0CRDejLELme6t6uZtMHqMSPGkJBM85oTUqP wtgA== X-Gm-Message-State: ACgBeo29HoxFDol7TNRla5mBF2AD/EVq5aNyx1dlq+3rXiIsdil/RXZ6 +gj5SMQi5rypY/JdsCca8RCm6divgt8= X-Google-Smtp-Source: AA6agR46uXnxQGKu9ULnyAc1BLhctUrVNAcVdLs11pJsS5/NKYX8LczIxzp8tXMl7eS110R8HE5vOzH3J7w= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:368c:b0:446:48d9:2be with SMTP id ej12-20020a056402368c00b0044648d902bemr6858842edb.167.1661526593376; Fri, 26 Aug 2022 08:09:53 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:59 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-37-glider@google.com> Subject: [PATCH v5 36/44] x86: kmsan: use __msan_ string functions where possible. From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 3b401fa0f3746..6c8a1a29d0b63 100644 --- a/include/linux/fortify-string.h +++ b/include/linux/fortify-string.h @@ -285,8 +285,10 @@ __FORTIFY_INLINE void fortify_memset_chk(__kernel_size= _t size, * __builtin_object_size() must be captured here to avoid evaluating argum= ent * side-effects further into the macro layers. */ +#ifndef CONFIG_KMSAN #define memset(p, c, s) __fortify_memset_chk(p, c, s, \ __builtin_object_size(p, 0), __builtin_object_size(p, 1)) +#endif =20 /* * To make sure the compiler can enforce protection against buffer overflo= ws, --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 3ABC0ECAAD4 for ; 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Fri, 26 Aug 2022 08:09:57 -0700 (PDT) Date: Fri, 26 Aug 2022 17:08:00 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-38-glider@google.com> Subject: [PATCH v5 37/44] x86: kmsan: sync metadata pages on page fault From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 fa71a5d12e872..d728791be8ace 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 3A72DECAAD4 for ; Fri, 26 Aug 2022 15:16:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344225AbiHZPQ1 (ORCPT ); Fri, 26 Aug 2022 11:16:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244437AbiHZPOq (ORCPT ); Fri, 26 Aug 2022 11:14:46 -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 C2CC874E2D for ; Fri, 26 Aug 2022 08:10:02 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id i6-20020a05640242c600b00447c00a776aso1250231edc.20 for ; Fri, 26 Aug 2022 08:10:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=G7zTeV7HivGGK7/AmFGwNvvgE+xYoTaOW1pCL0nph+s=; b=rllUU8td54J92uwD4gqMdf7quRrn9vs+RF/VGfmhTNifoonDDOGDzA+ehk2F0Nktis bzsb1L86DwkC+0Lwn7biXr7xSRRAyztcTTabYoOev0SalCjTFvsRPApNrtWrG92arrNL vYy30mjcDtboOMLaYF/EGB9Bb67OhSnqrd9929GMzB46msZdCnUGmupRwBiLOAMpOTu/ xgXxZRY8JK8LqcDPH4Z1qbgGAF+6QrIMppgLaa1fjdmq/jeISdUH5rHhnHGN0itBSODe GmUzrI95aXvhJ1Ss7JdEnAwqbHxBSkafgMVWr/h9flFgsjbzEK99uA8DU4lsh1XM5zFP k9rw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=G7zTeV7HivGGK7/AmFGwNvvgE+xYoTaOW1pCL0nph+s=; b=uBN/w5FYItL4Z3oK7YWakKY+Ywc68+CwAftzaKOyo0bNLA3q9cLrXmN8K6J4OuskKY qAz5A+Oea+0jmFiwPdRm+ohQzH0l1f9wk/mrW/yF2UJfAKmcHIQVmSnylS59LpIlfXLT 3HyRMVGdsY5sBNF1TpdkNCh6orTpbeg+ZE1cZ9DKwta/YSi8pgORU3CV0QUr1I6ZUAkb pCqtGYHle/PKEBgXeX3+1M4djNKR3QeWG50xWR37gV/ir2ITpxzgGPmCSeOynaOnuknT JqJm17bIRBzNhLNUU1cC57N6L0AvqGrowaYH/J1M2OzyRlgxBb7di6K8ppTwYnOeFzIM v7Eg== X-Gm-Message-State: ACgBeo0hFe6nVSUJvPwmY/mk+VdqXCIQ+MOn3noxgTnE73O7zneaPEZ5 ibXUxJF41RDDinzEy3v+Q2hkdLDqrW0= X-Google-Smtp-Source: AA6agR6mygGnpoLM0Fz1GI/HNspwZBf2HxeWieGPgMrRMoJDYKMR11CPv0kXU0SX1XneClLqmTxEKKFSAKQ= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a17:907:b17:b0:72a:edb8:7529 with SMTP id h23-20020a1709070b1700b0072aedb87529mr5717591ejl.749.1661526599889; Fri, 26 Aug 2022 08:09:59 -0700 (PDT) Date: Fri, 26 Aug 2022 17:08:01 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-39-glider@google.com> Subject: [PATCH v5 38/44] x86: kasan: kmsan: support CONFIG_GENERIC_CSUM on x86, enable it for KASAN/KMSAN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 f9920f1341c8d..33f4d4baba079 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -324,6 +324,10 @@ 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 AC8C9ECAAA3 for ; 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Fri, 26 Aug 2022 08:10:02 -0700 (PDT) Date: Fri, 26 Aug 2022 17:08:02 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-40-glider@google.com> Subject: [PATCH v5 39/44] x86: fs: kmsan: disable CONFIG_DCACHE_WORD_ACCESS From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 33f4d4baba079..697da8dae1418 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -128,7 +128,9 @@ 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 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 102C5ECAAA3 for ; Fri, 26 Aug 2022 15:16:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344139AbiHZPQe (ORCPT ); Fri, 26 Aug 2022 11:16:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46106 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344440AbiHZPO7 (ORCPT ); Fri, 26 Aug 2022 11:14:59 -0400 Received: from mail-wm1-x34a.google.com (mail-wm1-x34a.google.com [IPv6:2a00:1450:4864:20::34a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 82FD89A9C6 for ; Fri, 26 Aug 2022 08:10:09 -0700 (PDT) Received: by mail-wm1-x34a.google.com with SMTP id h133-20020a1c218b000000b003a5fa79008bso4191228wmh.5 for ; Fri, 26 Aug 2022 08:10:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=BglHskuQEcyUyCGOJUH508pmeGJAtuUxUacPJvhZbyk=; b=dLOEePxQJ3Q8NTUKaCKscxiPUndoB4UtDuE3c4k6e51Ijeopi1Q2jwY0fQKx91/gRV tjQCOKAvn8SFyX8Z/lnl+CXNB72GSSg2BB8Hq6Vt7SqvWnhLYEqRJylixp3qoaDTG2zm raV0B1FrZYeNKlh2L47/qDrSM5egy+WYAo9m1hFPEaFpdxuy6sh5qTqGIMfCAvjZyI9j 3naaSJ5illmzgZ7ldkbeAiiQNTjVVsYNVEYdyNBLpQSwjzyRINT8fbPdzQGGY0zreFu8 UWmcW7wtBNkjvMa2czQus+EuHAF96CwCURikCoYjx9Tb33q6CXTdGxIjYlAAIrQDAeMj IDGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=BglHskuQEcyUyCGOJUH508pmeGJAtuUxUacPJvhZbyk=; b=s+A4717zCg4bY836GpgVtcAt5ODOoHUBvwI3F6Abpt0k+ZicLQ1gifxbH8huFlczzW IsurGDhBcwi0VhswT1dNENaPYzMhba4mUrRLzv43BnZd4N+rLcTIoHLDxZSnLq1Tsy+c f77cfVyE0eJnuE51SBJS7ugMGmv+5DMjq1gevdciEUe1KmKmMfDnYetK0g+PeAFZj36w CQbpG4PV9cIbwxEX5bOu2G2OnSvI/f7YG/VvUk1j8H6OVsemLqOzBoS+lnXRfcq3Q4Wt gWv5Trj1gV239FeVsl5FY1+lpy4VxDqeufDFSksXE5FCMMMkk7wNpw0VfoSj/0hFM2x4 2Zag== X-Gm-Message-State: ACgBeo2Mdfy8QFFaRrgNlbR4Y+EriR/lOOu/IwN5bTCXyTIWQeGbJSSs cXmn3wPonOg9vmTcbcerxlw+Zl0O+6Q= X-Google-Smtp-Source: AA6agR6NknND7Ys7dLoaR0YpbVpHtssuPzgQY9WE+k93NXy2tjYdfG5ALV06XNy3sKThCmImd1fIcvZnQyg= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a5d:58d6:0:b0:226:cf81:f68d with SMTP id o22-20020a5d58d6000000b00226cf81f68dmr60412wrf.131.1661526605261; Fri, 26 Aug 2022 08:10:05 -0700 (PDT) Date: Fri, 26 Aug 2022 17:08:03 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-41-glider@google.com> Subject: [PATCH v5 40/44] x86: kmsan: don't instrument stack walking functions From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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" Upon function exit, KMSAN marks local variables as uninitialized. Further function calls may result in the compiler creating the stack frame where these local variables resided. This results in frame pointers being marked as uninitialized data, which is normally correct, because they are not stack-allocated. However stack unwinding functions are supposed to read and dereference the frame pointers, in which case KMSAN might be reporting uses of uninitialized values. To work around that, we mark update_stack_state(), unwind_next_frame() and show_trace_log_lvl() with __no_kmsan_checks, preventing all KMSAN reports inside those functions and making them return initialized values. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I6550563768fbb08aa60b2a96803= 675dcba93d802 --- arch/x86/kernel/dumpstack.c | 6 ++++++ arch/x86/kernel/unwind_frame.c | 11 +++++++++++ 2 files changed, 17 insertions(+) diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index afae4dd774951..476eb504084e4 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -177,6 +177,12 @@ static void show_regs_if_on_stack(struct stack_info *i= nfo, struct pt_regs *regs, } } =20 +/* + * This function reads pointers from the stack and dereferences them. The + * pointers may not have their KMSAN shadow set up properly, which may res= ult + * in false positive reports. Disable instrumentation to avoid those. + */ +__no_kmsan_checks static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *r= egs, unsigned long *stack, const char *log_lvl) { diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c index 8e1c50c86e5db..d8ba93778ae32 100644 --- a/arch/x86/kernel/unwind_frame.c +++ b/arch/x86/kernel/unwind_frame.c @@ -183,6 +183,16 @@ static struct pt_regs *decode_frame_pointer(unsigned l= ong *bp) } #endif =20 +/* + * While walking the stack, KMSAN may stomp on stale locals from other + * functions that were marked as uninitialized upon function exit, and + * now hold the call frame information for the current function (e.g. the = frame + * pointer). Because KMSAN does not specifically mark call frames as + * initialized, false positive reports are possible. To prevent such repor= ts, + * we mark the functions scanning the stack (here and below) with + * __no_kmsan_checks. + */ +__no_kmsan_checks static bool update_stack_state(struct unwind_state *state, unsigned long *next_bp) { @@ -250,6 +260,7 @@ static bool update_stack_state(struct unwind_state *sta= te, return true; } =20 +__no_kmsan_checks bool unwind_next_frame(struct unwind_state *state) { struct pt_regs *regs; --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 BC279ECAAA3 for ; Fri, 26 Aug 2022 15:16:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245673AbiHZPQg (ORCPT ); Fri, 26 Aug 2022 11:16:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344436AbiHZPO7 (ORCPT ); Fri, 26 Aug 2022 11:14:59 -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 C6715A61C8 for ; Fri, 26 Aug 2022 08:10:11 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id q32-20020a05640224a000b004462f105fa9so1240395eda.4 for ; Fri, 26 Aug 2022 08:10:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=VDn7tLtoTqUri5wCNae2jgpDMB9XRf/m0RZ2a2IuTLU=; b=XuSgIJWo5MH1NG3rWGo/F6MDltFcf2qPl6MCg/lTmi6AVs/W3AFN0L3RCnMqTlX9lr dKd/GckQv5Z6rSA+ayYP2KyxzcAyFxigMT3ptZSUl+gwPWVJSY9aubJhhTBy8zE+VVZx CGTMVKUA67P93/ZY15+zBfj4PaUpI6K4dk8spYaiA6AzXLDnbdicLnYpwutgnjjkOzyS hnFo1lTrpffm0Zz8iscFAwJfrYozG7CPI8rmN9qs3VLS/3azTHfOe6oXTOh5+hkHW5Bu RpNeHbpB3NC1YbvSkhEm3j/KxYQQRtFq+lVJn9jc6zvqweY5eCiiYGU2uk30ec6mXLQI dUWg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=VDn7tLtoTqUri5wCNae2jgpDMB9XRf/m0RZ2a2IuTLU=; b=QwgKMMVfuPD9N6FUg+F+aMzENi3B8fYrT/kTlA6TOkNfr8cCv10EYxeuOvS/PgIUbe /SPNklb9ULmhR3V0B6Aa59tf3B+JQby6qs5QoboyketIP1u2B/9yUDYOxCx0zzq3Ppmb ab5ki1L+smttj37WBsAFOYnrKwTUi8hWl1gGUOXU4nKork0l1zXMxB0jwVz1zpEnzuBI +iG3gnxyTbWeqkohYKREG0QJ8OEQIVu/GZzWLOBROu8K+eXQ7N70zjwfOezM7g5Wcger gL9rUgG8VejkVIjRBh9x/6L54KkxXw0OqdE5TRo69127x+Thtzg/M/dZhh8Ek7fM801p YyrA== X-Gm-Message-State: ACgBeo2CCB7HD/B8H6icfvLcjYwoRYx54B4USLl7FjR0GCcXowRpBflI JP6E8ClNfuRxVq1zQ/lWW2splYJQJ2w= X-Google-Smtp-Source: AA6agR7Aswd52JiieVR1uDzHxTIsNC8FPiPrY6f0RXtM2U6YqiEtATQBhicPX6UGtVM3aylaikgOQRe7gwE= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:1f87:b0:43b:b88d:1d93 with SMTP id c7-20020a0564021f8700b0043bb88d1d93mr7088766edc.314.1661526607921; Fri, 26 Aug 2022 08:10:07 -0700 (PDT) Date: Fri, 26 Aug 2022 17:08:04 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-42-glider@google.com> Subject: [PATCH v5 41/44] entry: kmsan: introduce kmsan_unpoison_entry_regs() From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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" struct pt_regs passed into IRQ entry code is set up by uninstrumented asm functions, therefore KMSAN may not notice the registers are initialized. kmsan_unpoison_entry_regs() unpoisons the contents of struct pt_regs, preventing potential false positives. Unlike kmsan_unpoison_memory(), it can be called under kmsan_in_runtime(), which is often the case in IRQ entry code. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Ibfd7018ac847fd8e5491681f508= ba5d14e4669cf --- include/linux/kmsan.h | 15 +++++++++++++++ kernel/entry/common.c | 5 +++++ mm/kmsan/hooks.c | 26 ++++++++++++++++++++++++++ 3 files changed, 46 insertions(+) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index 84dddf3aa5f8b..f4015a7546e39 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -238,6 +238,17 @@ void kmsan_handle_dma_sg(struct scatterlist *sg, int n= ents, */ void kmsan_handle_urb(const struct urb *urb, bool is_out); =20 +/** + * kmsan_unpoison_entry_regs() - Handle pt_regs in low-level entry code. + * @regs: struct pt_regs pointer received from assembly code. + * + * KMSAN unpoisons the contents of the passed pt_regs, preventing potential + * false positive reports. Unlike kmsan_unpoison_memory(), + * kmsan_unpoison_entry_regs() can be called from the regions where + * kmsan_in_runtime() returns true, which is the case in early entry code. + */ +void kmsan_unpoison_entry_regs(const struct pt_regs *regs); + #else =20 static inline void kmsan_init_shadow(void) @@ -334,6 +345,10 @@ static inline void kmsan_handle_urb(const struct urb *= urb, bool is_out) { } =20 +static inline void kmsan_unpoison_entry_regs(const struct pt_regs *regs) +{ +} + #endif =20 #endif /* _LINUX_KMSAN_H */ diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 063068a9ea9b3..846add8394c41 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -5,6 +5,7 @@ #include #include #include +#include #include #include #include @@ -24,6 +25,7 @@ static __always_inline void __enter_from_user_mode(struct= pt_regs *regs) user_exit_irqoff(); =20 instrumentation_begin(); + kmsan_unpoison_entry_regs(regs); trace_hardirqs_off_finish(); instrumentation_end(); } @@ -352,6 +354,7 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs = *regs) lockdep_hardirqs_off(CALLER_ADDR0); ct_irq_enter(); instrumentation_begin(); + kmsan_unpoison_entry_regs(regs); trace_hardirqs_off_finish(); instrumentation_end(); =20 @@ -367,6 +370,7 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs = *regs) */ lockdep_hardirqs_off(CALLER_ADDR0); instrumentation_begin(); + kmsan_unpoison_entry_regs(regs); rcu_irq_enter_check_tick(); trace_hardirqs_off_finish(); instrumentation_end(); @@ -452,6 +456,7 @@ irqentry_state_t noinstr irqentry_nmi_enter(struct pt_r= egs *regs) ct_nmi_enter(); =20 instrumentation_begin(); + kmsan_unpoison_entry_regs(regs); trace_hardirqs_off_finish(); ftrace_nmi_enter(); instrumentation_end(); diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index 58334fa32ff86..14d6c78a793b8 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -347,6 +347,32 @@ void kmsan_unpoison_memory(const void *address, size_t= size) } EXPORT_SYMBOL(kmsan_unpoison_memory); =20 +/* + * Version of kmsan_unpoison_memory() that can be called from within the K= MSAN + * runtime. + * + * Non-instrumented IRQ entry functions receive struct pt_regs from assemb= ly + * code. Those regs need to be unpoisoned, otherwise using them will resul= t in + * false positives. + * Using kmsan_unpoison_memory() is not an option in entry code, because t= he + * return value of in_task() is inconsistent - as a result, certain calls = to + * kmsan_unpoison_memory() are ignored. kmsan_unpoison_entry_regs() ensure= s that + * the registers are unpoisoned even if kmsan_in_runtime() is true in the = early + * entry code. + */ +void kmsan_unpoison_entry_regs(const struct pt_regs *regs) +{ + unsigned long ua_flags; + + if (!kmsan_enabled) + return; + + ua_flags =3D user_access_save(); + kmsan_internal_unpoison_memory((void *)regs, sizeof(*regs), + KMSAN_POISON_NOCHECK); + user_access_restore(ua_flags); +} + void kmsan_check_memory(const void *addr, size_t size) { if (!kmsan_enabled) --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 556B7ECAAD4 for ; Fri, 26 Aug 2022 15:16:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344394AbiHZPQn (ORCPT ); Fri, 26 Aug 2022 11:16:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344443AbiHZPPe (ORCPT ); Fri, 26 Aug 2022 11:15:34 -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 64B9ABA9F6 for ; Fri, 26 Aug 2022 08:10:15 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id qa35-20020a17090786a300b0073d4026a97dso718306ejc.9 for ; Fri, 26 Aug 2022 08:10:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=rCTBedHFoD5mjPc5axfz3IhJFNkE8btw4kiDfQuZoWM=; b=fg/g7W5SFXhbc3u2Ka10S6sfG+hleQgHtIujYd0emCXLuaRjW/Lp6/k4/2cWo7l/yp VDQQl06jPUO4V5hkPUjOfNuax5shhJaKnbpXyd21jWZdCRxSmNTw/c5xxG3zrihbz+OE Ljd50zcy2oKUZWQBLmYWsMOuW6qxf6tCX2W3+KQJUFv3PXm77b5Ak7Io2QiMeQ/oK9vK ZD8Tqs0aoGX8nDwtNuhyBXUzYeCZIaWWl/08zjdMFlG1dJKaN0WeEcKRi8ejkQvW4T1P wvM92OSrEzTbGCfmQLEw8aa8qLoI04nx9tn9Pj1TgR/4CFpWvS9JnaF3HfLp1oJuw/pj zqCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=rCTBedHFoD5mjPc5axfz3IhJFNkE8btw4kiDfQuZoWM=; b=48kUcZ0NnFGe3Ss/CC8T8+u43Ct8+5tikaa29+CBqEkKbcVXnvWZE7+fD4qnCISphN Z0m06uQR5XXETAGJGY18Pv9Oyvkq2fMM98S5ByLJkmr3qeA7Nri0a2Xq+Jc+PBfMezqV 0Ee43ZOLSHZqVuCMi2Nv0qQS2FRiHtX49Wu2a/FZx6kViPmSlw1XP4eEOfkfnOhLA1ds /vl3LSgN/HX/gZfMWt7FQTmMjHYdw7KchD4heiXlkFBxjd3gGbgwMQFWzaLDd/3wyJer zHn/+Gbw6efN1dZUEEd58AHn/UT6saAMe9Jxs+98grSWgW1/eX1xbn0PXknXpjCVFclc EEkQ== X-Gm-Message-State: ACgBeo3VxiVP0LFHMWyiBOreunJEPA7nGNwtOYqGWwgNiX97TS6u5n4J cu1/4JjeiA36yV/jaL8ZYYiLo1Ilyis= X-Google-Smtp-Source: AA6agR7tXjpYxk8MsRplqzj3thTzocuzhsrofVe2ZMXjeqhyHHZW7zWMaS3lAs0uR1Cb77CsZjqkIFO/xsw= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:2816:b0:434:ed38:16f3 with SMTP id h22-20020a056402281600b00434ed3816f3mr7084895ede.116.1661526610607; Fri, 26 Aug 2022 08:10:10 -0700 (PDT) Date: Fri, 26 Aug 2022 17:08:05 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-43-glider@google.com> Subject: [PATCH v5 42/44] bpf: kmsan: initialize BPF registers with zeroes From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 executing BPF programs, certain registers may get passed uninitialized to helper functions. E.g. when performing a JMP_CALL, registers BPF_R1-BPF_R5 are always passed to the helper, no matter how many of them are actually used. Passing uninitialized values as function parameters is technically undefined behavior, so we work around it by always initializing the registers. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I8ef9dbe94724cee5ad1e3a162f2= b805345bc0586 --- kernel/bpf/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index c1e10d088dbb7..547d139ab98af 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2002,7 +2002,7 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bp= f_insn *insn) static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bp= f_insn *insn) \ { \ u64 stack[stack_size / sizeof(u64)]; \ - u64 regs[MAX_BPF_EXT_REG]; \ + u64 regs[MAX_BPF_EXT_REG] =3D {}; \ \ FP =3D (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ ARG1 =3D (u64) (unsigned long) ctx; \ --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 9FBFDECAAD4 for ; Fri, 26 Aug 2022 15:16:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344424AbiHZPQr (ORCPT ); Fri, 26 Aug 2022 11:16:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46632 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344499AbiHZPPi (ORCPT ); Fri, 26 Aug 2022 11:15:38 -0400 Received: from mail-lf1-x14a.google.com (mail-lf1-x14a.google.com [IPv6:2a00:1450:4864:20::14a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E3DBBBA66 for ; Fri, 26 Aug 2022 08:10:16 -0700 (PDT) Received: by mail-lf1-x14a.google.com with SMTP id y3-20020a197503000000b00492f3a13baeso294275lfe.12 for ; Fri, 26 Aug 2022 08:10:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=dGjdyFKcPZ8AZlzw9ep1EXgYBHGgW0m7GguSz7kBI6Q=; b=DZGsI9l3W9MQLA+ou9XdSB4IZE46ComuEd6rS14iWZ0xSDfAJ+BWwB8A7M05fO5zjT Wh7mYAH6WAAzh+FI/uVm5Ljcf9NEeu2Z9UZM+4qfZzFoj+6Fh/tecr4Yol7TBl6MiU/L tCTqBg9m2iJte3DzNqf8V7ws94Br5Wtp68vVWk7plrk6xmxEjPcPZVSvIrk/LnFF/INL 93xvlWF5Ha1xHXpbxLntxctwzalog3vxzBxrVMuGDkqbsYK5RzyESy+/nuRwFZ41sSYu t2owLKhR+yzd+pCanHFbrVCWUmN1zsn8mhRcH/6ROVVHuRMuA9Jhn32qCWbGf06hi10p XV8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=dGjdyFKcPZ8AZlzw9ep1EXgYBHGgW0m7GguSz7kBI6Q=; b=LxFSpg+X03p3C7kvv8NQJ0Brx0lw1h8AcnmMeWsRRAh9eX3UVQPaoe32MVMZpoFwtt yCAOU8wApwwBpzDqxpKcF154FM0OLT9KvnltnZffk82EkwmJRHAjGu3IFKdsppK877uE eet1UMs2Gw2BFgNLEjGngqlD9XQlpDDVJDiEtvMRJ3rgsqpWRFlAWvVz0B7lSvQzIG0n P2vwHAAsiKJ4+bL4jSQwsieKuuxBk/UWX8DmasGgFxc2Kmk9nVb+Hqy1+OR01dOBo35Z wXpRzBgSxU24tne/UnDLh3K0hD31ZsPW1ADCid8bZncGxkxz1YaogKrqPcykBMlZUlZb zBcw== X-Gm-Message-State: ACgBeo0ojgE8UAIV7KmJ0pHGaTz4YuG0mc1IBfLOhCIZZ30Tt2oc0MVP MBB7/XUcc1NBoDBWOS5jUDuph3gKZlE= X-Google-Smtp-Source: AA6agR5+Ww/s7u4XD1azUk5I5ZYmSipZxiExxoopJysRcyPZ8zjk++GJnOf429p9ygUYKujEBktJ1Rf+Pzg= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6512:3054:b0:48a:f489:1d68 with SMTP id b20-20020a056512305400b0048af4891d68mr2401202lfb.260.1661526613226; Fri, 26 Aug 2022 08:10:13 -0700 (PDT) Date: Fri, 26 Aug 2022 17:08:06 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-44-glider@google.com> Subject: [PATCH v5 43/44] mm: fs: initialize fsdata passed to write_begin/write_end interface From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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 implementing the a_ops->write_end() interface accept the `void *fsdata` parameter that is supposed to be initialized by the corresponding a_ops->write_begin() (which accepts `void **fsdata`). However not all a_ops->write_begin() implementations initialize `fsdata` unconditionally, so it may get passed uninitialized to a_ops->write_end(), resulting in undefined behavior. Fix this by initializing fsdata with NULL before the call to write_begin(), rather than doing so in all possible a_ops implementations. This patch covers only the following cases found by running x86 KMSAN under syzkaller: - generic_perform_write() - cont_expand_zero() and generic_cont_expand_simple() - page_symlink() Other cases of passing uninitialized fsdata may persist in the codebase. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Ie300c21bbe9dea69a730745bd3c= 6d2720953bf41 --- fs/buffer.c | 4 ++-- fs/namei.c | 2 +- mm/filemap.c | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index 55e762a58eb65..e1198f4b28c8f 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -2352,7 +2352,7 @@ int generic_cont_expand_simple(struct inode *inode, l= off_t size) struct address_space *mapping =3D inode->i_mapping; const struct address_space_operations *aops =3D mapping->a_ops; struct page *page; - void *fsdata; + void *fsdata =3D NULL; int err; =20 err =3D inode_newsize_ok(inode, size); @@ -2378,7 +2378,7 @@ static int cont_expand_zero(struct file *file, struct= address_space *mapping, const struct address_space_operations *aops =3D mapping->a_ops; unsigned int blocksize =3D i_blocksize(inode); struct page *page; - void *fsdata; + void *fsdata =3D NULL; pgoff_t index, curidx; loff_t curpos; unsigned zerofrom, offset, len; diff --git a/fs/namei.c b/fs/namei.c index 53b4bc094db23..076ae96ca0b14 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -5088,7 +5088,7 @@ int page_symlink(struct inode *inode, const char *sym= name, int len) const struct address_space_operations *aops =3D mapping->a_ops; bool nofs =3D !mapping_gfp_constraint(mapping, __GFP_FS); struct page *page; - void *fsdata; + void *fsdata =3D NULL; int err; unsigned int flags; =20 diff --git a/mm/filemap.c b/mm/filemap.c index 15800334147b3..ada25b9f45ad1 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3712,7 +3712,7 @@ ssize_t generic_perform_write(struct kiocb *iocb, str= uct iov_iter *i) unsigned long offset; /* Offset into pagecache page */ unsigned long bytes; /* Bytes to write to page */ size_t copied; /* Bytes copied from user */ - void *fsdata; + void *fsdata =3D NULL; =20 offset =3D (pos & (PAGE_SIZE - 1)); bytes =3D min_t(unsigned long, PAGE_SIZE - offset, --=20 2.37.2.672.g94769d06f0-goog From nobody Tue Apr 7 14:52:31 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 7C69CECAAD4 for ; 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Fri, 26 Aug 2022 08:10:15 -0700 (PDT) Date: Fri, 26 Aug 2022 17:08:07 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-45-glider@google.com> Subject: [PATCH v5 44/44] x86: kmsan: enable KMSAN builds for x86 From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , 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 , kasan-dev@googlegroups.com, 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. Also declare x86-specific functions checking address validity in arch/x86/include/asm/kmsan.h. Signed-off-by: Alexander Potapenko --- v4: -- per Marco Elver's request, create arch/x86/include/asm/kmsan.h and move arch-specific inline functions there. Link: https://linux-review.googlesource.com/id/I1d295ce8159ce15faa496d20089= d953a919c125e --- arch/x86/Kconfig | 1 + arch/x86/include/asm/kmsan.h | 55 ++++++++++++++++++++++++++++++++++++ 2 files changed, 56 insertions(+) create mode 100644 arch/x86/include/asm/kmsan.h diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 697da8dae1418..bd9436cd0f29b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -168,6 +168,7 @@ 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 diff --git a/arch/x86/include/asm/kmsan.h b/arch/x86/include/asm/kmsan.h new file mode 100644 index 0000000000000..a790b865d0a68 --- /dev/null +++ b/arch/x86/include/asm/kmsan.h @@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * x86 KMSAN support. + * + * Copyright (C) 2022, Google LLC + * Author: Alexander Potapenko + */ + +#ifndef _ASM_X86_KMSAN_H +#define _ASM_X86_KMSAN_H + +#ifndef MODULE + +#include +#include + +/* + * Taken from arch/x86/mm/physaddr.h to avoid using an instrumented versio= n. + */ +static inline bool 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 true; +} + +/* + * Taken from arch/x86/mm/physaddr.c to avoid using an instrumented versio= n. + */ +static inline 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); +} + +#endif /* !MODULE */ + +#endif /* _ASM_X86_KMSAN_H */ --=20 2.37.2.672.g94769d06f0-goog