From mboxrd@z Thu Jan 1 00:00:00 1970 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 4A182C43219 for ; Tue, 29 Mar 2022 12:55:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236919AbiC2M4t (ORCPT ); Tue, 29 Mar 2022 08:56:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52428 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237045AbiC2M41 (ORCPT ); Tue, 29 Mar 2022 08:56:27 -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 55F8E25D5F5 for ; Tue, 29 Mar 2022 05:42:33 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id er8-20020a170907738800b006e003254d86so8131052ejc.11 for ; Tue, 29 Mar 2022 05:42:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=0QWUQ+RqE8jiHyj7/O+KujG6tRpsbOFA8yuMseJPgVs=; b=OfXq72ZoBUQGSWSvm4KVtJ07Y6J70d5V6dAjwsYPNQ8KvQs+UemAzoD9b+EXKX/OTw Q+izHPhM0oLIkOLIiuKDw0qaaM3HmxBX8q8lxNCUTVCL6uMVfLhs0yBqTwJyZYo3a2Dd PHMlh5zEbtKHkaJRb6sAKEdQbGhEcA7fqUGVsUSQYvLsCZPqYBZ6kCgNZI+IIO0DTiYw dKXtVOTB8fspK7u9aonJCNi788zBxPM+etWoLtYNpYHL5mhBEusrVsXgVIm9RsvEQvVL BVUcgD1GuztoqNHxl+h1HcQQt1n0AN97ckOSFFHrUUEbkVxi2NvTa3+e0HN0zz3+BFfO qT4Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=0QWUQ+RqE8jiHyj7/O+KujG6tRpsbOFA8yuMseJPgVs=; b=29Xd3CQpdAj5uIWBEeDDjtOdKapplxelBbxB0JKyWJlV1PuLXRiNsI1lXTJdI6KgCe 43iIjLVEq5aNGYgjfyT/VOUmKrza+AfdJl5HvDT+xZ1NPD+GO1xq04ppuyIiEuQ5RSaO T3ybzneu3zXnXI3aZeUyGIZlcrzCGV2jOkQ8x6oEvX4x2baOi0EusIOtDnw8ln+X3Cbp MDDJTt3z0zuuUH8Is5i5AWqWueSEtihQNphLV+PYVCFQvh5C727Vtqq2TGLuMkdT12Zj OuWz04yd1JAl3DRFO4ewJhFtmXO0h2eO6gw0g+MRJlplkqJGSe4KoJdlwSzxR7Kv1aXz XAZw== X-Gm-Message-State: AOAM533DVXhh8oS4EZtnSb7B2xAMyKiucQrY08Emx49g9PwJmAL8WaVQ R9TtFO7NuIMvO8D+sQAdZBsPWamwAK4= X-Google-Smtp-Source: ABdhPJytokWuo6v19GSWg2KLHdtKqtVYC2QIF6Shk0LT4bep8x7ZGLJY2F5r9sIe9kWDKcupdjioDqnZsL8= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:36eb:759:798f:98c3]) (user=glider job=sendgmr) by 2002:a17:906:948:b0:6d6:e479:1fe4 with SMTP id j8-20020a170906094800b006d6e4791fe4mr33417649ejd.240.1648557751382; Tue, 29 Mar 2022 05:42:31 -0700 (PDT) Date: Tue, 29 Mar 2022 14:40:15 +0200 In-Reply-To: <20220329124017.737571-1-glider@google.com> Message-Id: <20220329124017.737571-47-glider@google.com> Mime-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> X-Mailer: git-send-email 2.35.1.1021.g381101b075-goog Subject: [PATCH v2 46/48] x86: fs: kmsan: disable CONFIG_DCACHE_WORD_ACCESS From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Andrey Konovalov Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org 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/I4c0073224ac2897cafb8c037362c49dda9cfa133 --- arch/x86/Kconfig | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 86df15017f79d..646a7849be4cf 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -126,7 +126,9 @@ config X86 select CLKEVT_I8253 select CLOCKSOURCE_VALIDATE_LAST_CYCLE select CLOCKSOURCE_WATCHDOG - select DCACHE_WORD_ACCESS + # Word-size accesses may read uninitialized data past the trailing \0 + # in strings and cause false KMSAN reports. + select DCACHE_WORD_ACCESS if !KMSAN select DYNAMIC_SIGFRAME select EDAC_ATOMIC_SCRUB select EDAC_SUPPORT -- 2.35.1.1021.g381101b075-goog