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 B2BC1C6FA89 for ; Thu, 15 Sep 2022 15:09:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230407AbiIOPJi (ORCPT ); Thu, 15 Sep 2022 11:09:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48374 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230389AbiIOPHh (ORCPT ); Thu, 15 Sep 2022 11:07:37 -0400 Received: from mail-ed1-x549.google.com (mail-ed1-x549.google.com [IPv6:2a00:1450:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 601C097EF3 for ; Thu, 15 Sep 2022 08:05:48 -0700 (PDT) Received: by mail-ed1-x549.google.com with SMTP id w20-20020a05640234d400b00450f24c8ca6so13151382edc.13 for ; Thu, 15 Sep 2022 08:05:48 -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=PRETZsLeKtd8er/vGZIvwJ67UbRQnpYPS7VnNd6iitc=; b=IWkX75T/Q/431JKoP2sw1gGv+TRTk4KNLPsHPqPmF3DWGGkurKMl+8ONAEiBTDmheE /bRfKFH3UY7lflgk+tGWw2/6W93k+canHKGQEEM6HO9CEQKXMkCUdWv2f4MdMGWOzrIJ G1jDnp7yxG83XTB77HooBd8pj1DXFnHlOsQNax7eY08XATzldTmtPTs26zPGXzgiy0Mz qNMjVTPKt1EwXBmVdFMqJwU0Hi3WzmYliSNKgIFTflzD9qXlcsCQbN9DI90LX0j/d90o XtOjNQuQkTbxe0CH70hTFyO24aVCsu/CiMUIXLlZA1dstaOwJf3am2bgGgOOrjIMUJcm Q/jQ== 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=PRETZsLeKtd8er/vGZIvwJ67UbRQnpYPS7VnNd6iitc=; b=G2J4yJKptS5lkPGSRfj7jIwd4u7IZYMVIiQl/rqDhjRr9tHr3QMiZpy4TBsVVMVDEE JVV+k+gxaOTPn5TbTju9afd4C7srQEt2chNTbcdcwXWpWQ5QcumxeC2vmfhAnvBYjISG W9FwGi5G7hMA5N50EZ5y63vGXeQ0ZYL8/9YrjJfL56S0lMMrOaiivvrqQmbSUmREFsXl HDemNsiN0QbNaT40hFhhr8rMBLDHhJLpKaz9Dtws+0Uc7iMVhCOgESmpVJQUT0tK531u Mdggt/6Daq1dIcASea//+7n3SRMJtxzUOxBkIJWrnUG0TYlqUP/NYzWLC1ugg0nYrPys 3LJQ== X-Gm-Message-State: ACrzQf3wzHCj9Dco4yhaaWBQW4I2xcIIBjPcPOROtyL++bPP2KSu5pLj D1QbKI4xhg80OzG5j3jX2NUdhwAYhDc= X-Google-Smtp-Source: AMsMyM6VUn1IGxuterUYBQnBqfqJp+t0ecAEWvO8gXW0QL3/We8FwA+dhbmbRRZVNw5aXpi14wf65X3+jsg= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:686d:27b5:495:85b7]) (user=glider job=sendgmr) by 2002:a17:906:cc59:b0:779:f094:af3d with SMTP id mm25-20020a170906cc5900b00779f094af3dmr278250ejb.239.1663254346675; Thu, 15 Sep 2022 08:05:46 -0700 (PDT) Date: Thu, 15 Sep 2022 17:03:59 +0200 In-Reply-To: <20220915150417.722975-1-glider@google.com> Mime-Version: 1.0 References: <20220915150417.722975-1-glider@google.com> X-Mailer: git-send-email 2.37.2.789.g6183377224-goog Message-ID: <20220915150417.722975-26-glider@google.com> Subject: [PATCH v7 25/43] kmsan: disable strscpy() optimization under KMSAN 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 Biggers , 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 , Stephen Rothwell , 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Disable the efficient 8-byte reading under KMSAN to avoid false positives. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/Iffd8336965e88fce915db2e6a9d6524422975f69 --- lib/string.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/lib/string.c b/lib/string.c index 6f334420f6871..3371d26a0e390 100644 --- a/lib/string.c +++ b/lib/string.c @@ -197,6 +197,14 @@ ssize_t strscpy(char *dest, const char *src, size_t count) max = 0; #endif + /* + * read_word_at_a_time() below may read uninitialized bytes after the + * trailing zero and use them in comparisons. Disable this optimization + * under KMSAN to prevent false positive reports. + */ + if (IS_ENABLED(CONFIG_KMSAN)) + max = 0; + while (max >= sizeof(unsigned long)) { unsigned long c, data; -- 2.37.2.789.g6183377224-goog