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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 07E29C31E40 for ; Tue, 6 Aug 2019 21:37:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF7C72187F for ; Tue, 6 Aug 2019 21:37:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565127451; bh=a4djyiScQqeYcYWQDIRQUAM0biKXX3DU8s+BDCvoG2g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=rhQPomqtYYyV8LGH514dpKneGn3PaUY2rRQcurBwrlv4e6+w/8SaGnF7OJJ9+PoAj D9GvCaRltwEzaopdadQicNsYIQzINt68roKSrkkfasZcKZ/5nF662MPWrlBXo9FZaq hSFRTvOUgDu0RbSCiPn08expF7wNGMh+pSFhyNOc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729354AbfHFVhb (ORCPT ); Tue, 6 Aug 2019 17:37:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:55212 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728430AbfHFVh2 (ORCPT ); Tue, 6 Aug 2019 17:37:28 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1E00121881; Tue, 6 Aug 2019 21:37:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565127447; bh=a4djyiScQqeYcYWQDIRQUAM0biKXX3DU8s+BDCvoG2g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zkJXA5jjCuSpCGyK0J/pJL+rP7fZUFk3JOTtVgVKtfK70fqlgc0hA0+ZxIxe3T4qR yY2Q//jSkNW+yU6KQQvIjYdmBYI8cRalrPHGTa6J/nAccugfu8mHzJ6qW26jcE2+/i t9TsnBl+dRctplUF2b5Jm8JtYYMo71k45CscJ3no= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Numfor Mbiziwo-Tiapo , Alexander Shishkin , Ian Rogers , Jiri Olsa , Mark Drayton , Namhyung Kim , Peter Zijlstra , Song Liu , Stephane Eranian , Arnaldo Carvalho de Melo , Sasha Levin , clang-built-linux@googlegroups.com Subject: [PATCH AUTOSEL 4.9 05/17] perf header: Fix use of unitialized value warning Date: Tue, 6 Aug 2019 17:37:02 -0400 Message-Id: <20190806213715.20487-5-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190806213715.20487-1-sashal@kernel.org> References: <20190806213715.20487-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Numfor Mbiziwo-Tiapo [ Upstream commit 20f9781f491360e7459c589705a2e4b1f136bee9 ] When building our local version of perf with MSAN (Memory Sanitizer) and running the perf record command, MSAN throws a use of uninitialized value warning in "tools/perf/util/util.c:333:6". This warning stems from the "buf" variable being passed into "write". It originated as the variable "ev" with the type union perf_event* defined in the "perf_event__synthesize_attr" function in "tools/perf/util/header.c". In the "perf_event__synthesize_attr" function they allocate space with a malloc call using ev, then go on to only assign some of the member variables before passing "ev" on as a parameter to the "process" function therefore "ev" contains uninitialized memory. Changing the malloc call to zalloc to initialize all the members of "ev" which gets rid of the warning. To reproduce this warning, build perf by running: make -C tools/perf CLANG=1 CC=clang EXTRA_CFLAGS="-fsanitize=memory\ -fsanitize-memory-track-origins" (Additionally, llvm might have to be installed and clang might have to be specified as the compiler - export CC=/usr/bin/clang) then running: tools/perf/perf record -o - ls / | tools/perf/perf --no-pager annotate\ -i - --stdio Please see the cover letter for why false positive warnings may be generated. Signed-off-by: Numfor Mbiziwo-Tiapo Cc: Alexander Shishkin Cc: Ian Rogers Cc: Jiri Olsa Cc: Mark Drayton Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Song Liu Cc: Stephane Eranian Link: http://lkml.kernel.org/r/20190724234500.253358-2-nums@google.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/util/header.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 693dcd4ea6a38..61e3c482935ad 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -2943,7 +2943,7 @@ int perf_event__synthesize_attr(struct perf_tool *tool, size += sizeof(struct perf_event_header); size += ids * sizeof(u64); - ev = malloc(size); + ev = zalloc(size); if (ev == NULL) return -ENOMEM; -- 2.20.1