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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76B35C433EF for ; Tue, 14 Dec 2021 16:43:33 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C002F6B00A8; Tue, 14 Dec 2021 11:23:48 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id BAEDC6B00A9; Tue, 14 Dec 2021 11:23:48 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A50496B00AA; Tue, 14 Dec 2021 11:23:48 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0202.hostedemail.com [216.40.44.202]) by kanga.kvack.org (Postfix) with ESMTP id 963656B00A8 for ; Tue, 14 Dec 2021 11:23:48 -0500 (EST) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 5FFCC8908A for ; Tue, 14 Dec 2021 16:23:38 +0000 (UTC) X-FDA: 78916920516.14.4F6B87D Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) by imf04.hostedemail.com (Postfix) with ESMTP id F027940016 for ; Tue, 14 Dec 2021 16:23:37 +0000 (UTC) Received: by mail-wm1-f74.google.com with SMTP id k25-20020a05600c1c9900b00332f798ba1dso13396579wms.4 for ; Tue, 14 Dec 2021 08:23:37 -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=329hfiTw4u/5iPPx3u5+w8IXpCrQT+Keh+FFx6WQcZuZ/oYj+Xf+99af/KnoDXZoqE XycolFP0ww/jtC5zzE2+MhVKIRsXadAu1Yonrw/326XxTZXOgA1z34IY7fHAVstZ5sUr SgyqQRE76HMKlTJCWrKA0ln1QQmBtwjyZvN6J19OKeEBPxHcWmhfvry3nBmtlToSWvTx JVFvz+OBqhIkEXbz1RoLyMbS/z9pE6GlwEpO56xdYss8EnRoNS1lkg61HURQmW2RvIkJ KRsdmI7cgRyZOF1fghmolP9oclKB9d2DSX+gG2RLOn+1KW/n5eB8hMz3cwstWu0wKmSX ixwg== X-Gm-Message-State: AOAM531uTTXFYnvZESy/ZlZr4MYYt/8Jw/+3hCQAAPcTzk+CgHYl/Hkz cYtA6fPmTpPoJ1IeR5x4jDT+8vZglqY= 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" X-Stat-Signature: xoxjdfztwdkz6ds6fwg5zuygh5zzrqwm Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=WoieykU0; spf=pass (imf04.hostedemail.com: domain of 3CMW4YQYKCIktyvqr4t11tyr.p1zyv07A-zzx8npx.14t@flex--glider.bounces.google.com designates 209.85.128.74 as permitted sender) smtp.mailfrom=3CMW4YQYKCIktyvqr4t11tyr.p1zyv07A-zzx8npx.14t@flex--glider.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: F027940016 X-HE-Tag: 1639499017-948892 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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