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 E02A1C433F5 for ; Tue, 26 Apr 2022 16:49:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353484AbiDZQw0 (ORCPT ); Tue, 26 Apr 2022 12:52:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353253AbiDZQvZ (ORCPT ); Tue, 26 Apr 2022 12:51:25 -0400 Received: from mail-ej1-x64a.google.com (mail-ej1-x64a.google.com [IPv6:2a00:1450:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D9A5488AB for ; Tue, 26 Apr 2022 09:46:16 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id hr35-20020a1709073fa300b006f3647cd980so5655265ejc.5 for ; Tue, 26 Apr 2022 09:46:16 -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=PvvQOkeWxb6tin1r/OdBpIQ8hVIbIwFgBKLY/n662Oo1Yc2gzkT3RFavBCrcUDflLs To1X4x/SsydH6Gjq4FDxgOoM7VqwnFsKE92qeV1cla2+rLg0szhkMHP461cEk36yD6ck TFM8yhVnJC1HPGjZePU2ds4uXwzpo5psB26UvrvZmakkP7hLnlkT/0uBFeQ3c3deJrFi E2LDgaPSxmWx4JfBwiy8atnQY9a6ykOa4FT6CRl3yZ1uo6IwzOvjtkmzv+Rwq9TvxZPC 3YZhoFaRJADOVgggx8HQ+eTvA64+eAD/kYhejvkot2bEKIdmS94vZAYYzE9trd0JGX2p 3ynA== X-Gm-Message-State: AOAM533z3HeKgR6SbeNYFBG0MBPxRSsc9rRYE5TAiZBaOqNqPc/iHBBY KGTB7bXjAeFsaSx1+M5g0tTlTV2vNes= 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" 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 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