From nobody Tue Apr 7 16:31:00 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