From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752692AbcGMH0f (ORCPT ); Wed, 13 Jul 2016 03:26:35 -0400 Received: from terminus.zytor.com ([198.137.202.10]:42226 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751678AbcGMH0c (ORCPT ); Wed, 13 Jul 2016 03:26:32 -0400 Date: Wed, 13 Jul 2016 00:26:17 -0700 From: tip-bot for Jiri Olsa Message-ID: Cc: hpa@zytor.com, mingo@kernel.org, a.p.zijlstra@chello.nl, acme@redhat.com, namhyung@kernel.org, dsahern@gmail.com, linux-kernel@vger.kernel.org, jolsa@kernel.org, tglx@linutronix.de Reply-To: hpa@zytor.com, mingo@kernel.org, linux-kernel@vger.kernel.org, jolsa@kernel.org, tglx@linutronix.de, acme@redhat.com, a.p.zijlstra@chello.nl, dsahern@gmail.com, namhyung@kernel.org In-Reply-To: <1468148882-10362-5-git-send-email-jolsa@kernel.org> References: <1468148882-10362-5-git-send-email-jolsa@kernel.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf python: Fix pyrf_evlist__read_on_cpu event consuming Git-Commit-ID: e8968e654191390a1300f0847250353a1c9da30d 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: e8968e654191390a1300f0847250353a1c9da30d Gitweb: http://git.kernel.org/tip/e8968e654191390a1300f0847250353a1c9da30d Author: Jiri Olsa AuthorDate: Sun, 10 Jul 2016 13:07:56 +0200 Committer: Arnaldo Carvalho de Melo CommitDate: Tue, 12 Jul 2016 16:16:44 -0300 perf python: Fix pyrf_evlist__read_on_cpu event consuming We can't consume the event before parsing it. Under heavy load we could get caught by kernel writer overwriting the event we're trying to parse. Signed-off-by: Jiri Olsa Cc: David Ahern Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1468148882-10362-5-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/python.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c index d0c1267..c68ef03 100644 --- a/tools/perf/util/python.c +++ b/tools/perf/util/python.c @@ -865,12 +865,14 @@ static PyObject *pyrf_evlist__read_on_cpu(struct pyrf_evlist *pevlist, PyObject *pyevent = pyrf_event__new(event); struct pyrf_event *pevent = (struct pyrf_event *)pyevent; - perf_evlist__mmap_consume(evlist, cpu); - if (pyevent == NULL) return PyErr_NoMemory(); err = perf_evlist__parse_sample(evlist, event, &pevent->sample); + + /* Consume the even only after we parsed it out. */ + perf_evlist__mmap_consume(evlist, cpu); + if (err) return PyErr_Format(PyExc_OSError, "perf: can't parse sample, err=%d", err);