From: Tony Jones tonyj@suse.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@entry=0xb2a200 <rt_stat>, new_entry=new_entry@entry=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@entry=727442, cpu=cpu@entry=0, st=0xb2a200 <rt_stat>) at util/stat-shadow.c:239 config=config@entry=0xafeb40 <stat_config>, 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
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@suse.de Reviewed-by: Jiri Olsa jolsa@kernel.org Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Tested-by: Ravi Bangoria ravi.bangoria@linux.ibm.com Cc: Andi Kleen ak@linux.intel.com Cc: Jin Yao yao.jin@linux.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@redhat.com Signed-off-by: Sasha Levin sashal@kernel.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 5c070a600233a..d8791e0e5f75b 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c @@ -1633,13 +1633,8 @@ 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) @@ -2305,6 +2300,8 @@ 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;