From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Olsa Subject: Re: [PATCH] perf script: fix crash when processing recorded stat data Date: Sun, 20 Jan 2019 23:01:21 +0100 Message-ID: <20190120220121.GE8591@krava> References: <20190120191414.12925-1-tonyj@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190120191414.12925-1-tonyj@suse.de> Sender: linux-kernel-owner@vger.kernel.org To: Tony Jones Cc: linux-perf-users@vger.kernel.org, acme@kernel.org, Jin Yao , ak@linux.intel.com, linux-kernel@vger.kernel.org List-Id: linux-perf-users.vger.kernel.org On Sun, Jan 20, 2019 at 11:14:14AM -0800, Tony Jones wrote: > While updating Perf to work with Python3 and Python2 I noticed that the > stat-cpi script was dumping core. > > $ perf stat -e cycles,instructions record -o /tmp/perf.data /bin/false > > Performance counter stats for '/bin/false': > > 802,148 cycles > > 604,622 instructions 802,148 cycles > 604,622 instructions > > 0.001445842 seconds time elapsed > > $ perf script -i /tmp/perf.data -s scripts/python/stat-cpi.py > Segmentation fault (core dumped) > ... > ... > rblist=rblist@entry=0xb2a200 , > new_entry=new_entry@entry=0x7ffcb755c310) at util/rblist.c:33 > ctx=, type=, create=, > cpu=, evsel=) at util/stat-shadow.c:118 > ctx=, type=, st=) > at util/stat-shadow.c:196 > count=count@entry=727442, cpu=cpu@entry=0, st=0xb2a200 ) > at util/stat-shadow.c:239 > config=config@entry=0xafeb40 , > counter=counter@entry=0x133c6e0) at util/stat.c:372 > ... > ... > > The issue is that since 1fcd03946b52 perf_stat__update_shadow_stats now calls > update_runtime_stat passing rt_stat rather than calling update_stats but > perf_stat__init_shadow_stats has never been called to initialize rt_stat in > the script path processing recorded stat data. > > Since I can't see any reason why perf_stat__init_shadow_stats() is presently > initialized like it is in builtin-script.c::perf_sample__fprint_metric() > [4bd1bef8bba2f] I'm proposing it instead be initialized once in __cmd_script > > Fixes: 1fcd03946b52 ("perf stat: Update per-thread shadow stats") > Signed-off-by: Tony Jones > --- > tools/perf/builtin-script.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c > index d079f36d342d..9a6dd86e606f 100644 > --- a/tools/perf/builtin-script.c > +++ b/tools/perf/builtin-script.c > @@ -1681,13 +1681,8 @@ static void perf_sample__fprint_metric(struct perf_script *script, > .force_header = false, > }; > struct perf_evsel *ev2; > - static bool init; > u64 val; > > - if (!init) { > - perf_stat__init_shadow_stats(); > - init = true; > - } well, there's no need to use shadow stats until stat data is processed.. but it's actually just a static initialization, so there's no need for late init Reviewed-by: Jiri Olsa thanks, jirka > if (!evsel->stats) > perf_evlist__alloc_stats(script->session->evlist, false); > if (evsel_script(evsel->leader)->gnum++ == 0) > @@ -2359,6 +2354,8 @@ static int __cmd_script(struct perf_script *script) > > signal(SIGINT, sig_handler); > > + perf_stat__init_shadow_stats(); > + > /* override event processing functions */ > if (script->show_task_events) { > script->tool.comm = process_comm_event; > -- > 2.18.0 >