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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,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 AF1F7C433E9 for ; Tue, 2 Mar 2021 07:48:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 68B1861494 for ; Tue, 2 Mar 2021 07:48:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1576716AbhCBEcM (ORCPT ); Mon, 1 Mar 2021 23:32:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1443746AbhCBCgR (ORCPT ); Mon, 1 Mar 2021 21:36:17 -0500 Received: from mail-wm1-x334.google.com (mail-wm1-x334.google.com [IPv6:2a00:1450:4864:20::334]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D559CC06178B for ; Mon, 1 Mar 2021 18:35:36 -0800 (PST) Received: by mail-wm1-x334.google.com with SMTP id n22so935874wmc.2 for ; Mon, 01 Mar 2021 18:35:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=uHGDVsiyTsA6DF1ecftcK5dyYlXaVZKVulssJgFfiKI=; b=emGI1AdpwcPQ1t6mgydrDfQlJHF7SRMWZOF04hpmcxJCRDqYhzXYbCwH6igKTeXJJj Ao0yQd+eIykWvxsMd9L8NOkDrq02y2Guo8mg4zY3JZahy4LK8DeczHi68NK+W+tyZ+OA 4xk8lDLKiXHsrz3I9jaYW3OnDzSgZoSxFBjg3jPFEEmQaoR9Xmh2q+xuJRU1zuq8rEN6 D8moemGtlQg/Q3+UZ+1agznqfP10ZVnv0xgeWEd3f+39ijgOIJLNjMl6d+OvIraOKdTj Tw0JPeIlVx7eFPu8UurJHritoK8UYWuvOug70Or2PyhMKVHVUuz/JT+LyCchtfm6S3xI VR0A== 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=uHGDVsiyTsA6DF1ecftcK5dyYlXaVZKVulssJgFfiKI=; b=C2AGd/XIA6fXmi+b0C6Y0d3YxQOE9+ld9DI2+wZG7za0onFbjKXvL8vk726VtDqSjj /FM+2Dss5Ihq4GK0LqhABKzUtWplugnr1h0QweY+YEYC1oeFJiRLjmorVosv35ePfWQ7 iV6Bsqgi967Q8Y+lmSBTOYbc6/1ZhhL8B42zjHGhBTSh5rRtI7wbHmYAp4T6nGCglQfS kTd/on0Bn7N2+TsQF+1/cOO8jUrsAN7VroxXSkB70YcJ+FTB24yWTk8HbPbOk8RjC5+w mZbKf9QGt2rOryemq+FbnCe2pPOYHPJ5RCYxHL7NohB4gUFyg1kaqvGtfc1/E8fTiVZg 4g/w== X-Gm-Message-State: AOAM531vgDdHXVSBFVZmL52Ex0g9iMn4plAP4hkc6ZcI5Ch6ms1PEFl5 zIS5uwW11LRNaOPfo01vKQXM2HZXRqLX4bSZ X-Google-Smtp-Source: ABdhPJzv1ZFqTHlc2amjCso3PGMVl7yeRYvIW6AYKgzpxd9QEzkqmxm1aSkX/zrJYOIujglSLyyAOA== X-Received: by 2002:a05:600c:4ec6:: with SMTP id g6mr1649980wmq.2.1614652535381; Mon, 01 Mar 2021 18:35:35 -0800 (PST) Received: from localhost.localdomain ([2a02:8084:e84:2480:228:f8ff:fe6f:83a8]) by smtp.gmail.com with ESMTPSA id l6sm9993382wrm.71.2021.03.01.18.35.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Mar 2021 18:35:35 -0800 (PST) From: Dmitry Safonov To: linux-kernel@vger.kernel.org Cc: Dmitry Safonov <0x7f454c46@gmail.com>, Dmitry Safonov , Alexander Shishkin , Arnaldo Carvalho de Melo , Ingo Molnar , Jiri Olsa , Mark Rutland , Namhyung Kim , Peter Zijlstra Subject: [PATCH] perf diff: Don't crash on freeing errno-session Date: Tue, 2 Mar 2021 02:35:33 +0000 Message-Id: <20210302023533.1572231-1-dima@arista.com> X-Mailer: git-send-email 2.30.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org __cmd_diff() sets result of perf_session__new() to d->session. In case of failure, it's errno and perf-diff may crash with: failed to open perf.data: Permission denied Failed to open perf.data Segmentation fault (core dumped) >From the coredump: 0 0x00005569a62b5955 in auxtrace__free (session=0xffffffffffffffff) at util/auxtrace.c:2681 1 0x00005569a626b37d in perf_session__delete (session=0xffffffffffffffff) at util/session.c:295 2 perf_session__delete (session=0xffffffffffffffff) at util/session.c:291 3 0x00005569a618008a in __cmd_diff () at builtin-diff.c:1239 4 cmd_diff (argc=, argv=) at builtin-diff.c:2011 [..] Funny enough, it won't always crash. For me it crashes only if failed file is second in cmd-line: the reason is that cmd_diff() check files for branch-stacks [in check_file_brstack()] and if the first file doesn't have brstacks, it doesn't proceed to try open other files from cmd-line. Check d->session before calling perf_session__delete(). Another solution would be assigning to temporary variable, checking it, but I find it easier to follow with IS_ERR() check in the same function. After some time it's still obvious why the check is needed, and with temp variable it's possible to make the same mistake. Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Signed-off-by: Dmitry Safonov --- tools/perf/builtin-diff.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c index cefc71506409..b0c57e55052d 100644 --- a/tools/perf/builtin-diff.c +++ b/tools/perf/builtin-diff.c @@ -1236,7 +1236,8 @@ static int __cmd_diff(void) out_delete: data__for_each_file(i, d) { - perf_session__delete(d->session); + if (!IS_ERR(d->session)) + perf_session__delete(d->session); data__free(d); } -- 2.30.1