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 6F7FEC43217 for ; Tue, 14 Dec 2021 16:24:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236030AbhLNQYZ (ORCPT ); Tue, 14 Dec 2021 11:24:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236060AbhLNQXr (ORCPT ); Tue, 14 Dec 2021 11:23:47 -0500 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 4B148C061374 for ; Tue, 14 Dec 2021 08:23:38 -0800 (PST) Received: by mail-wm1-x34a.google.com with SMTP id j71-20020a1c234a000000b00342f418ae7cso13417257wmj.1 for ; Tue, 14 Dec 2021 08:23:38 -0800 (PST) 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=YXzf2AmImQ6mywVvUf+Dd2SadORvaqMGa98N/8wEyCE=; b=WoieykU0vE3e7pyI/oyga8gaBev/YztJjf73B/DEvIxeumtlBa6EUTmjuc4jcmIMLX nVUK3c6ez+TVQFQQ2qMETFAL6aiqaRThJuloL8YuWdGBKZ5ep7MSrmnoDQm4AO9kgdAl Wh4CgLx/HAje1tAx7yMO3KMwNXVBThP1eOIpJDnxdyxM+4UrOYrM4a/bX/s2rpzdsiwU w83IY5U7lohcI5Alm77PKO3vv8zFBRwoiJyz1TJ9O0g6pUWPazaH/MqKhRKEXIDVDco2 g1gKxls5sjcT3gjd3g4b5NOHfK6sfVPvNX4hIXL++00vy5xc7dkvJxn86YqeRYlTuU4F FuEw== 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=YXzf2AmImQ6mywVvUf+Dd2SadORvaqMGa98N/8wEyCE=; b=0ml/rh2jNLTdxUfeEiBstjskqfH9/7WEaVmJQu+ehm7UxBlUOXSza7ShuXxI6uAngR 9z8kuPJJGxM6IO1L7IZkSKKimNxl+23EtXH3dkfcYVUGS5cKuVpWN0E+pmRvTbkLjXXx axj6vJ8N1nNhfWJjcobdrlIIaC8u9tSGhuxaLg9ocFKD9OM45bTY+z8za1yOx+fg0jcj tPQlWSLNQ4IZOpR+/dBM5E31FT08ho9wHqegg5rUtOS7K5UruNej7TMS2lt7YTlImx/y 5kXnPhZHCGdPnWFEy3pSu+vnCLnbv8S6I6N2nQPah7a3PIKh8IHh1x/LMI36men4mig8 Nk5w== X-Gm-Message-State: AOAM532vywhcRjJDOJD7lCgVDeyFYaxoCyVPfx6OjNXhThDW83lhg4QF jRWJQUBwAy2SJ2iJgRmqg+EBkmljhS8= X-Google-Smtp-Source: ABdhPJwPL8nrsavt08DbsW8quI6O5ixz52gAqZYkOXc5DfWMgtMM43VM2EUKGgLQG6hcWYM+aM6wKoh/iSg= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:357e:2b9d:5b13:a652]) (user=glider job=sendgmr) by 2002:a5d:6111:: with SMTP id v17mr6757949wrt.512.1639499016732; Tue, 14 Dec 2021 08:23:36 -0800 (PST) Date: Tue, 14 Dec 2021 17:20:45 +0100 In-Reply-To: <20211214162050.660953-1-glider@google.com> Message-Id: <20211214162050.660953-39-glider@google.com> Mime-Version: 1.0 References: <20211214162050.660953-1-glider@google.com> X-Mailer: git-send-email 2.34.1.173.g76aa8bc2d0-goog Subject: [PATCH 38/43] x86: fs: kmsan: disable CONFIG_DCACHE_WORD_ACCESS From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Ard Biesheuvel , 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 , 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 760570ff3f3e4..0dc77352bc3c9 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -125,7 +125,9 @@ 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 -- 2.34.1.173.g76aa8bc2d0-goog