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 BABF4C433EF for ; Tue, 26 Apr 2022 16:46:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5D36C6B007E; Tue, 26 Apr 2022 12:46:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5859B6B0080; Tue, 26 Apr 2022 12:46:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4031A6B0088; Tue, 26 Apr 2022 12:46:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.27]) by kanga.kvack.org (Postfix) with ESMTP id 3225B6B007E for ; Tue, 26 Apr 2022 12:46:17 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 0DD6826CA6 for ; Tue, 26 Apr 2022 16:46:17 +0000 (UTC) X-FDA: 79399607994.04.DC5569C Received: from mail-ej1-f73.google.com (mail-ej1-f73.google.com [209.85.218.73]) by imf08.hostedemail.com (Postfix) with ESMTP id 7EB9F160046 for ; Tue, 26 Apr 2022 16:46:10 +0000 (UTC) Received: by mail-ej1-f73.google.com with SMTP id go12-20020a1709070d8c00b006f009400732so9167609ejc.1 for ; Tue, 26 Apr 2022 09:46:15 -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=qZO+Ar5AUQjZ17sp8HnLfJ3bnZDmnQ4HtehVjR2RSag=; b=Pt5+odsaPLVLA+BIkFaOGZ5z3uWJenSne3f73BJt4PbanWkfmtsct7CN0wAO2xN5gU Yhaxk8FOCzZhswyeeTNVL8OMhm9c/T3iPCztTqmlZxSpLpgMOs6YXH5MZ/fx+97iCGvz zddbne3cp5tk6W6voA6FNsecjeKs0yW1DQ4Tz30W1QM+yA9fVauckWd7D4HpMMiv8n/u VNAOuyzoM5s6YO+8DH4/mHKvxm5uilD1LTm5hSJS1BnACQmJdUQmedoVo1JHnrQYqad/ JlxuIlepoOSV3NlP0UfaMmhcA4Fr+PZ2URCMg+I0v/ZRX2C/u5IO3EAmXGa2X6k+fRQb I4UQ== 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=qZO+Ar5AUQjZ17sp8HnLfJ3bnZDmnQ4HtehVjR2RSag=; b=zlXOr0bhWTa++kTb2rEUgccjL1n0Z8AbUpezRnJR2nwTe3v7mU2yebfsuFc/51G+kr YqU6fyeXKGHltFqfcf0Bt3qwGTbHrfnSp0FE5lWp4Qf11q2XexNigeCqT58fwiNd6isg pCs3M1Pp52EktU0ha6SBt5VgGHMJyu3x2Of8/7Q/DpPsfPmnJhVKxM5r3qj+NG9sVEbW n6o/GJRWTOCUKqYkJz+xNmLEbHC163cx1kBSouO6hH2O8lBKF8XYRpyJD/xWbdVZpiXC EmStODnQTtxQW0QDze1aayHoHOhiM2a66Xomwggu2NYNai+MAxG7jB8KEyrQihw7vo1V OmOw== X-Gm-Message-State: AOAM533b/dMYwWwTeSxOXgi14BeVlAS5BFLTHDhHau0ItodRy1ls+t0I 2b+9lJ1J/nDPS4/BsLIamq4vmrX20hE= X-Google-Smtp-Source: ABdhPJwC/1Ho3LFpscyKKysPm+tD7uHD3uvu1NdPCEt5vju65j1NkGkMRTYyimkaio71xSi48PC422JlIc4= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:d580:abeb:bf6d:5726]) (user=glider job=sendgmr) by 2002:a05:6402:2689:b0:422:15c4:e17e with SMTP id w9-20020a056402268900b0042215c4e17emr26075746edd.33.1650991574553; Tue, 26 Apr 2022 09:46:14 -0700 (PDT) Date: Tue, 26 Apr 2022 18:43:13 +0200 In-Reply-To: <20220426164315.625149-1-glider@google.com> Message-Id: <20220426164315.625149-45-glider@google.com> Mime-Version: 1.0 References: <20220426164315.625149-1-glider@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v3 44/46] 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 , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Andrey Konovalov Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 7EB9F160046 X-Stat-Signature: jebhzf8xh8sbwexfnq7n114b71au4ydr X-Rspam-User: Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=Pt5+odsa; spf=pass (imf08.hostedemail.com: domain of 31iFoYgYKCNM5A723G5DD5A3.1DBA7CJM-BB9Kz19.DG5@flex--glider.bounces.google.com designates 209.85.218.73 as permitted sender) smtp.mailfrom=31iFoYgYKCNM5A723G5DD5A3.1DBA7CJM-BB9Kz19.DG5@flex--glider.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com X-HE-Tag: 1650991570-32126 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 ee5e6fd65bf1d..3209073f96415 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 -- 2.36.0.rc2.479.g8af0fa9b8e-goog