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Date: Sat, 23 Feb 2019 16:05:44 -0500 From: Sasha Levin <sashal@...nel.org> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org Cc: Tony Jones <tonyj@...e.de>, Andi Kleen <ak@...ux.intel.com>, Jin Yao <yao.jin@...ux.intel.com>, Arnaldo Carvalho de Melo <acme@...hat.com>, Sasha Levin <sashal@...nel.org> Subject: [PATCH AUTOSEL 4.19 09/65] perf script: Fix crash when processing recorded stat data From: Tony Jones <tonyj@...e.de> [ Upstream commit 8bf8c6da53c2265aea365a1de6038f118f522113 ] 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@...ry=0xb2a200 <rt_stat>, new_entry=new_entry@...ry=0x7ffcb755c310) at util/rblist.c:33 ctx=<optimized out>, type=<optimized out>, create=<optimized out>, cpu=<optimized out>, evsel=<optimized out>) at util/stat-shadow.c:118 ctx=<optimized out>, type=<optimized out>, st=<optimized out>) at util/stat-shadow.c:196 count=count@...ry=727442, cpu=cpu@...ry=0, st=0xb2a200 <rt_stat>) at util/stat-shadow.c:239 config=config@...ry=0xafeb40 <stat_config>, counter=counter@...ry=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 Committer testing: After applying the patch: # perf script -i /tmp/perf.data -s tools/perf/scripts/python/stat-cpi.py 0.001970: cpu -1, thread -1 -> cpi 1.709079 (1075684/629394) # No segfault. Signed-off-by: Tony Jones <tonyj@...e.de> Reviewed-by: Jiri Olsa <jolsa@...nel.org> Tested-by: Arnaldo Carvalho de Melo <acme@...hat.com> Tested-by: Ravi Bangoria <ravi.bangoria@...ux.ibm.com> Cc: Andi Kleen <ak@...ux.intel.com> Cc: Jin Yao <yao.jin@...ux.intel.com> Fixes: 1fcd03946b52 ("perf stat: Update per-thread shadow stats") Link: http://lkml.kernel.org/r/20190120191414.12925-1-tonyj@suse.de Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com> Signed-off-by: Sasha Levin <sashal@...nel.org> --- 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 ce2aee11e3605..53c11fc0855ee 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c @@ -1589,13 +1589,8 @@ 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; - } if (!evsel->stats) perf_evlist__alloc_stats(script->session->evlist, false); if (evsel_script(evsel->leader)->gnum++ == 0) @@ -2214,6 +2209,8 @@ 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; -- 2.19.1
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