From nobody Sun Feb 8 19:39:46 2026 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 B7E81C74A5B for ; Fri, 24 Mar 2023 00:19:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230456AbjCXATd (ORCPT ); Thu, 23 Mar 2023 20:19:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230375AbjCXATb (ORCPT ); Thu, 23 Mar 2023 20:19:31 -0400 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D5B4193F7; Thu, 23 Mar 2023 17:19:26 -0700 (PDT) Received: by mail-pj1-x1035.google.com with SMTP id h12-20020a17090aea8c00b0023d1311fab3so77346pjz.1; Thu, 23 Mar 2023 17:19:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1679617165; x=1682209165; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:sender:from:to:cc:subject:date:message-id:reply-to; bh=suA1jKhcCOcixXpCVcZ12id0ImQVSXHARQLzFn5G688=; b=K8yiMNIxCIwbaoE1vowESnH4hmdNOEIlQEDou+HVvhwgdL7eFWV0JyW5TQ89hgccGB whgyLfye3QllyjiS8MwJ4OyalsouO58WrU2EICYmFr1F/S8GZSMNt6a+BbWNsSc088QE 2faYgpmsKgx57c7bAri/bWZ/u2V+WjJ45qL4m/DPjJ1a/YyX97neS5AMnSerBo6bswbJ Sfysmo08c9M/IsJ88ODIskzd+iQmB0HJ2U92auyyYB1Np/j0GKH6hrUChrH5YQcKAa5G SlmIezxPiNVmSnWeg8oNGggiGMsZLCMfOaNWxQEQiYFKhDYC0DPJUF9ypT38wAVp4uPc 5ydQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679617165; x=1682209165; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:sender:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=suA1jKhcCOcixXpCVcZ12id0ImQVSXHARQLzFn5G688=; b=mlXKMLh79i78wlbA7XtHW/ZIxo/fH1A6nHP2AapWaTm0RUo3yGQkgHMdOmPMDFIWJj DDCsDN+m7c1oVXR6MXrb29dP54hHalKRFrtZdYcXeTlHBADo/5vRcKqShVUiBrmRtTVE e5I+z2966ayfepk0i+XECb2xV3qywWqD/ajakfgHmB4FOriGNC9YD3Y7r80QoY2K/fUx yKq0C0Q4+bLVqTMxLXnYFY9U+zcCwdFPkLebqvY3aCGuOLH4KF4kF9qNlBVgFE+nelOc Ho3KFoqPLRuBzEIsGcNHH5YQi/2XdmzZHsv2FnneAuuc9FLObDykPq1W/nvi/+BBljVT bvkw== X-Gm-Message-State: AAQBX9e/kVCJ/7NhYbmrQfh2KhmdO1ZH/UKT2Vhw57AMNMghqnxBp8Bk 1xwm0QAfP72y8aonq6lJq3jIeMK/0iU= X-Google-Smtp-Source: AKy350ZAajLtafXS2eumPKcAZTQWHAgGg4qFsVyTIdctzYlBvd9M6SM/mLwWVQMYikGr/MYnVYpf2g== X-Received: by 2002:a17:903:32d1:b0:1a1:80ea:4352 with SMTP id i17-20020a17090332d100b001a180ea4352mr943126plr.0.1679617165387; Thu, 23 Mar 2023 17:19:25 -0700 (PDT) Received: from moohyul.svl.corp.google.com ([2620:15c:2d4:203:77d1:5545:2244:c784]) by smtp.gmail.com with ESMTPSA id m3-20020a63fd43000000b004facdf070d6sm12292278pgj.39.2023.03.23.17.19.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Mar 2023 17:19:24 -0700 (PDT) Sender: Namhyung Kim From: Namhyung Kim To: Arnaldo Carvalho de Melo , Jiri Olsa Cc: Ian Rogers , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org Subject: [PATCH] perf lock contention: Fix msan issue in lock_contention_read() Date: Thu, 23 Mar 2023 17:19:22 -0700 Message-Id: <20230324001922.937634-1-namhyung@kernel.org> X-Mailer: git-send-email 2.40.0.348.gf938b09366-goog MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" I got a report of a msan failure like below: $ sudo perf lock con -ab -- sleep 1 ... =3D=3D224416=3D=3DWARNING: MemorySanitizer: use-of-uninitialized-value #0 0x5651160d6c96 in lock_contention_read util/bpf_lock_contention.c= :290:8 #1 0x565115f90870 in __cmd_contention builtin-lock.c:1919:3 #2 0x565115f90870 in cmd_lock builtin-lock.c:2385:8 #3 0x565115f03a83 in run_builtin perf.c:330:11 #4 0x565115f03756 in handle_internal_command perf.c:384:8 #5 0x565115f02d53 in run_argv perf.c:428:2 #6 0x565115f02d53 in main perf.c:562:3 #7 0x7f43553bc632 in __libc_start_main #8 0x565115e865a9 in _start It was because the 'key' variable is not initialized. Actually it'd be set by bpf_map_get_next_key() but msan didn't seem to understand it. Let's make msan happy by initializing the variable. Signed-off-by: Namhyung Kim Acked-by: Ian Rogers --- tools/perf/util/bpf_lock_contention.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lo= ck_contention.c index 235fc7150545..5927bf0bd92b 100644 --- a/tools/perf/util/bpf_lock_contention.c +++ b/tools/perf/util/bpf_lock_contention.c @@ -249,7 +249,7 @@ static const char *lock_contention_get_name(struct lock= _contention *con, int lock_contention_read(struct lock_contention *con) { int fd, stack, err =3D 0; - struct contention_key *prev_key, key; + struct contention_key *prev_key, key =3D {}; struct contention_data data =3D {}; struct lock_stat *st =3D NULL; struct machine *machine =3D con->machine; --=20 2.40.0.348.gf938b09366-goog