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 00518ECAAD5 for ; Mon, 5 Sep 2022 12:33:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238227AbiIEMdM (ORCPT ); Mon, 5 Sep 2022 08:33:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60590 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237654AbiIEMbn (ORCPT ); Mon, 5 Sep 2022 08:31:43 -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 8453461701 for ; Mon, 5 Sep 2022 05:26:48 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id qw34-20020a1709066a2200b00730ca5a94bfso2270180ejc.3 for ; Mon, 05 Sep 2022 05:26:48 -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:subject:date; bh=y7GARGHGPpfPMqaRIp9ae7D7QgvYSCiDFPeV4nzQ3Rk=; b=ddTOCduO5x6A/vNQMTAUwanA9sA0BCMeAUh+AbwWZsHDAk9+85xCqrDPAoy/kXj/yM pZSbfcwBzuznV/e1nsCZpHlDb15U84fy2lfiqZMe8aoHY/I7P25KzOs1d3vrlFmbReSY CMgox+WoZoI864HUj6y69WtC8wXEhJsfJO1HGhmgOHeHxH+VxZafKqFKdLrvdFRpq+z3 ENymG35akVbdRkGAMGE8Z8s0OdqqWY6HbsmxVcinzKH7wWkH7p+aAzFkQtSI/s7mr3da ilHo8C+mpJ4L2avMdUVG4qeyBVv1yqdqrzQBpWWV9P63dsr6gXP1A1YwiJarV7ILSOFv WffQ== 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:subject:date; bh=y7GARGHGPpfPMqaRIp9ae7D7QgvYSCiDFPeV4nzQ3Rk=; b=buv5hIn8m5999+wgq4bUltWxLp8ktEwGpSNe67WO+6iBZGQhJeDlwty/hgNKONfwF0 bVfX3TQ7hlP8kFhlCPX8xyrS2MDgca/AZp148jppbDSvpHMDUQWdNDCau+lscENQGjnh dd5QSfWI97GSI8RE18bXsnKFSrZ3kszBgbUdGBCH29m6+kvyUtETXGFrV+obLemM3GEo cmhQoe1loM4aVvipdcN6jibcSwUyF0eAC95p/rZaXObO6rOT9HuFqWl6oJau38+NQcGq NbgPwdcEuqzK0HFYZck1BH48KXzWywf6rFo/z1vQUjVHP0qb+Rrkeb86FzQJM4ee09bR g17w== X-Gm-Message-State: ACgBeo2nOXYLeSqohN1lBVCbF83Tahjzyw6KdSbt+bM3oXqvTY4vyFVe A4pH+WRZSfhiOFbXq7hPn20WGDo1q5g= X-Google-Smtp-Source: AA6agR4QT5xvR//Dr9lpspZ++6X8QeAx9PC0zKsZbmb97U5jvQ2WfdBoaCZHo4G5Gg4skY0cmggOzLItUto= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:b808:8d07:ab4a:554c]) (user=glider job=sendgmr) by 2002:a17:906:fe46:b0:730:ca2b:cb7b with SMTP id wz6-20020a170906fe4600b00730ca2bcb7bmr37494826ejb.703.1662380804705; Mon, 05 Sep 2022 05:26:44 -0700 (PDT) Date: Mon, 5 Sep 2022 14:24:47 +0200 In-Reply-To: <20220905122452.2258262-1-glider@google.com> Mime-Version: 1.0 References: <20220905122452.2258262-1-glider@google.com> X-Mailer: git-send-email 2.37.2.789.g6183377224-goog Message-ID: <20220905122452.2258262-40-glider@google.com> Subject: [PATCH v6 39/44] x86: fs: kmsan: disable CONFIG_DCACHE_WORD_ACCESS 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, Andrey Konovalov Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 33f4d4baba079..697da8dae1418 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 -- 2.37.2.789.g6183377224-goog