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 X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B975C43219 for ; Thu, 2 May 2019 15:36:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C751420449 for ; Thu, 2 May 2019 15:36:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="J04pm3ui" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728772AbfEBPgK (ORCPT ); Thu, 2 May 2019 11:36:10 -0400 Received: from mail-ed1-f65.google.com ([209.85.208.65]:43736 "EHLO mail-ed1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728343AbfEBPgH (ORCPT ); Thu, 2 May 2019 11:36:07 -0400 Received: by mail-ed1-f65.google.com with SMTP id w33so179230edb.10 for ; Thu, 02 May 2019 08:36:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=IeCbek7GxN78jmKl6HDSULctY9a079sA8sLhO9KSXCE=; b=J04pm3uinBZj07mQUc20QoDfp+OQk/UzptzIcSRRvJQ+i19xBQyz7UfnOlAK1p63BP 0hBiwZvxaaLGWRcC+VrF0LkpwlOR1UA1i2R3snOKvD7L2UbudEv8MjBkKgtRLhI5AK64 +ajHM23pkTed/0m9GmNqamhAvr7SzAISWxzAKDHmUrK7V7yni2jLai0IAq33C+iJDI5n vys9SsRMh2mmR4MMQ4o/E9FfPT9tqsg1pQgNNbAYJbopon/cuMATXAkju4JdqQI80A8U lE4FFPwdswVeraFDpUWin5auZ+HT9MMpiC8xpByUz81NDaAJFOqUD+QQqbi6NYSx46e+ Ns1A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=IeCbek7GxN78jmKl6HDSULctY9a079sA8sLhO9KSXCE=; b=XyK0qIn7ohpy0aWCZp/EDVGa5Kx7kl1UWHeqNuThe0natSz7GH+eJtmEwLSfqOhZnq 3g6oSt1wPPOnCfpBC1b+0Pm76NFFiSVL0M/qrAhBcCQ3TmIbCy8xsW7hqbGmC+xQchHi dLcAWvjxYqbbJWOLrfM7LSJs8Um1EkqcAegn3wsVVYQ5+YXCwSvZC4NIfwoniJJXme5P b1Xj9Al+itYOWl1l8RcpheW2iYC+ZU5M8So1maAnGDyHL25tBlqTVWF5vdChZbXArXus +LgdV9Ebpzl54U1rH4vgp1/eJ0rKSzMicUH66XPJ5dq1T/eH0o9zwouMe4RonX6zbTp1 qMiA== X-Gm-Message-State: APjAAAXeIcbvxaOTaKLPft4gKLPVKnK7TyfEFR6P++5sRYsqp93Qv1uG 6tF2F8fNHZ58d1BbbMs34sk= X-Google-Smtp-Source: APXvYqx2dUlDAJbP5jPeB6xQOpTTqQTTzZYY1NEWzH8taBIya6BsF/hTANqdbRNRRF/OpyE8xQJ/mg== X-Received: by 2002:a50:be01:: with SMTP id a1mr3094467edi.12.1556811365468; Thu, 02 May 2019 08:36:05 -0700 (PDT) Received: from localhost.localdomain ([2a01:4f9:2b:2b84::2]) by smtp.gmail.com with ESMTPSA id e18sm7386693ejf.77.2019.05.02.08.36.04 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 02 May 2019 08:36:04 -0700 (PDT) From: Nathan Chancellor To: Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov Cc: kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Nick Desaulniers , clang-built-linux@googlegroups.com, Nathan Chancellor Subject: [PATCH] kasan: Zero initialize tag in __kasan_kmalloc Date: Thu, 2 May 2019 08:35:38 -0700 Message-Id: <20190502153538.2326-1-natechancellor@gmail.com> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 X-Patchwork-Bot: notify Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When building with -Wuninitialized and CONFIG_KASAN_SW_TAGS unset, Clang warns: mm/kasan/common.c:484:40: warning: variable 'tag' is uninitialized when used here [-Wuninitialized] kasan_unpoison_shadow(set_tag(object, tag), size); ^~~ set_tag ignores tag in this configuration but clang doesn't realize it at this point in its pipeline, as it points to arch_kasan_set_tag as being the point where it is used, which will later be expanded to (void *)(object) without a use of tag. Just zero initialize tag, as it removes this warning and doesn't change the meaning of the code. Link: https://github.com/ClangBuiltLinux/linux/issues/465 Signed-off-by: Nathan Chancellor --- mm/kasan/common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 36afcf64e016..4c5af68f2a8b 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -464,7 +464,7 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, { unsigned long redzone_start; unsigned long redzone_end; - u8 tag; + u8 tag = 0; if (gfpflags_allow_blocking(flags)) quarantine_reduce(); -- 2.21.0