From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752932AbeC2N6i (ORCPT ); Thu, 29 Mar 2018 09:58:38 -0400 Received: from terminus.zytor.com ([198.137.202.136]:33893 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752899AbeC2N6h (ORCPT ); Thu, 29 Mar 2018 09:58:37 -0400 Date: Thu, 29 Mar 2018 06:58:26 -0700 From: tip-bot for Kan Liang Message-ID: Cc: jolsa@kernel.org, kan.liang@linux.intel.com, tglx@linutronix.de, acme@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, wangnan0@huawei.com, namhyung@kernel.org, mingo@kernel.org Reply-To: linux-kernel@vger.kernel.org, wangnan0@huawei.com, mingo@kernel.org, namhyung@kernel.org, jolsa@kernel.org, acme@redhat.com, tglx@linutronix.de, kan.liang@linux.intel.com, hpa@zytor.com In-Reply-To: <1522071729-16776-1-git-send-email-kan.liang@linux.intel.com> References: <1522071729-16776-1-git-send-email-kan.liang@linux.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf mmap: Fix accessing unmapped mmap in perf_mmap__read_done() Git-Commit-ID: f58385f629c87a9e210108b39c1f4950d0363ad2 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: f58385f629c87a9e210108b39c1f4950d0363ad2 Gitweb: https://git.kernel.org/tip/f58385f629c87a9e210108b39c1f4950d0363ad2 Author: Kan Liang AuthorDate: Mon, 26 Mar 2018 09:42:09 -0400 Committer: Arnaldo Carvalho de Melo CommitDate: Tue, 27 Mar 2018 13:13:38 -0300 perf mmap: Fix accessing unmapped mmap in perf_mmap__read_done() There is a segmentation fault when running 'perf trace'. For example: [root@jouet e]# perf trace -e *chdir -o /tmp/bla perf report --ignore-vmlinux -i ../perf.data The perf_mmap__consume() could unmap the mmap. It needs to check the refcnt in perf_mmap__read_done(). Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Kan Liang Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Fixes: ee023de05f35 ("perf mmap: Introduce perf_mmap__read_done()") Link: http://lkml.kernel.org/r/1522071729-16776-1-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/mmap.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c index 38ca3ffb9d61..f6cfc52ff1fe 100644 --- a/tools/perf/util/mmap.c +++ b/tools/perf/util/mmap.c @@ -317,5 +317,11 @@ out: */ void perf_mmap__read_done(struct perf_mmap *map) { + /* + * Check if event was unmapped due to a POLLHUP/POLLERR. + */ + if (!refcount_read(&map->refcnt)) + return; + map->prev = perf_mmap__read_head(map); }