From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752271AbcBEOVv (ORCPT ); Fri, 5 Feb 2016 09:21:51 -0500 Received: from szxga01-in.huawei.com ([58.251.152.64]:13319 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753893AbcBEOEb (ORCPT ); Fri, 5 Feb 2016 09:04:31 -0500 From: Wang Nan To: Alexei Starovoitov , Arnaldo Carvalho de Melo , Arnaldo Carvalho de Melo , Brendan Gregg CC: Adrian Hunter , Cody P Schafer , "David S. Miller" , He Kuang , =?UTF-8?q?J=C3=A9r=C3=A9mie=20Galarneau?= , Jiri Olsa , Kirill Smelkov , Li Zefan , Masami Hiramatsu , Namhyung Kim , Peter Zijlstra , , Wang Nan , Subject: [PATCH 05/54] perf data: Fix releasing event_class Date: Fri, 5 Feb 2016 14:01:30 +0000 Message-ID: <1454680939-24963-6-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1454680939-24963-1-git-send-email-wangnan0@huawei.com> References: <1454680939-24963-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020205.56B4AB95.0163,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 039316953043a74fd104021a6d7f6bcd Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A new patch of libbabeltrace [1] reveals a object leak problem in perf data CTF support: perf code never release event_class which is allocated in add_event() and stored in evsel's private field. If libbabeltrace has the above patch applied, leaking event_class prevent writer being destroied and flushing metadata. For example: $ ./perf record ls Lowering default frequency rate to 500. Please consider tweaking /proc/sys/kernel/perf_event_max_sample_rate. perf.data [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.012 MB perf.data (12 samples) ] $ ./perf data convert --to-ctf ./out.ctf [ perf data convert: Converted 'perf.data' into CTF data './out.ctf' ] [ perf data convert: Converted and wrote 0.000 MB (12 samples) ] $ cat ./out.ctf/metadata $ ls -l ./out.ctf/metadata -rw-r----- 1 w00229757 mm 0 Jan 27 10:49 ./out.ctf/metadata The correct result should be: ... $ cat ./out.ctf/metadata /* CTF 1.8 */ trace { [SNIP] $ ls -l ./out.ctf/metadata -rw-r----- 1 w00229757 mm 2446 Jan 27 10:52 ./out.ctf/metadata The full story is: Patch [1] of babeltrace redesign reference counting scheme. In that patch: * writer <- trace (bt_ctf_writer_create) * trace <- stream_class (bt_ctf_trace_add_stream_class) * stream_class <- event_class (bt_ctf_stream_class_add_event_class) ('<-' means 'is a parent of') Holding of event_class causes reference count of corresponding 'writer' increases through parent chain. Perf expect 'writer' is released (so metadata is flushed) through bt_ctf_writer_put() in ctf_writer__cleanup(). However, since it never release event_class, the reference of 'writer' won't be reduced, so bt_ctf_writer_put() won't lead releasing of writer. Before this CTF patch, !(writer <- trace). Even event_class leak, writer is able to be released. [1] https://github.com/efficios/babeltrace/commit/e6a8e8e4744633807083a077ff9f101eb97d9801 Signed-off-by: Wang Nan Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Jérémie Galarneau Cc: Zefan Li Cc: pi3orama@163.com --- tools/perf/util/data-convert-bt.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/tools/perf/util/data-convert-bt.c b/tools/perf/util/data-convert-bt.c index 34cd1e4..b722e57 100644 --- a/tools/perf/util/data-convert-bt.c +++ b/tools/perf/util/data-convert-bt.c @@ -858,6 +858,23 @@ static int setup_events(struct ctf_writer *cw, struct perf_session *session) return 0; } +static void cleanup_events(struct perf_session *session) +{ + struct perf_evlist *evlist = session->evlist; + struct perf_evsel *evsel; + + evlist__for_each(evlist, evsel) { + struct evsel_priv *priv; + + priv = evsel->priv; + bt_ctf_event_class_put(priv->event_class); + zfree(&evsel->priv); + } + + perf_evlist__delete(evlist); + session->evlist = NULL; +} + static int setup_streams(struct ctf_writer *cw, struct perf_session *session) { struct ctf_stream **stream; @@ -1171,6 +1188,7 @@ int bt_convert__perf2ctf(const char *input, const char *path, bool force) (double) c.events_size / 1024.0 / 1024.0, c.events_count); + cleanup_events(session); perf_session__delete(session); ctf_writer__cleanup(cw); -- 1.8.3.4