From patchwork Wed Jan 27 11:21:05 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 60616 Delivered-To: patch@linaro.org Received: by 10.112.130.2 with SMTP id oa2csp2520795lbb; Wed, 27 Jan 2016 03:21:47 -0800 (PST) X-Received: by 10.66.193.195 with SMTP id hq3mr23970518pac.38.1453893707220; Wed, 27 Jan 2016 03:21:47 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id y69si8928442pfi.233.2016.01.27.03.21.46; Wed, 27 Jan 2016 03:21:47 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932224AbcA0LVp (ORCPT + 30 others); Wed, 27 Jan 2016 06:21:45 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:54079 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932168AbcA0LVh (ORCPT ); Wed, 27 Jan 2016 06:21:37 -0500 Received: from 172.24.1.47 (EHLO szxeml428-hub.china.huawei.com) ([172.24.1.47]) by szxrg03-dlp.huawei.com (MOS 4.4.3-GA FastPath queued) with ESMTP id BVG91160; Wed, 27 Jan 2016 19:21:23 +0800 (CST) Received: from linux-4hy3.site (10.107.193.248) by szxeml428-hub.china.huawei.com (10.82.67.183) with Microsoft SMTP Server id 14.3.235.1; Wed, 27 Jan 2016 19:21:16 +0800 From: Wang Nan To: CC: , Wang Nan , Jiri Olsa , =?UTF-8?q?J=C3=A9r=C3=A9mie=20Galarneau?= , Zefan Li , Subject: [PATCH] perf data: Fix releasing event_class Date: Wed, 27 Jan 2016 11:21:05 +0000 Message-ID: <1453893665-20530-1-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 MIME-Version: 1.0 X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020206.56A8A834.0027, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: b79eba415d8f69e4a705f089e7e4ea15 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk 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 | 14 ++++++++++++++ 1 file changed, 14 insertions(+) -- 1.8.3.4 diff --git a/tools/perf/util/data-convert-bt.c b/tools/perf/util/data-convert-bt.c index 34cd1e4..e553321 100644 --- a/tools/perf/util/data-convert-bt.c +++ b/tools/perf/util/data-convert-bt.c @@ -858,6 +858,19 @@ 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); + } +} + static int setup_streams(struct ctf_writer *cw, struct perf_session *session) { struct ctf_stream **stream; @@ -1171,6 +1184,7 @@ 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);