• T
    perf script: Fix crash when processing recorded stat data · d5f05016
    Tony Jones 提交于
    [ 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 1fcd0394 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()
    [4bd1bef8] 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: NTony Jones <tonyj@suse.de>
    Reviewed-by: NJiri Olsa <jolsa@kernel.org>
    Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
    Tested-by: NRavi Bangoria <ravi.bangoria@linux.ibm.com>
    Cc: Andi Kleen <ak@linux.intel.com>
    Cc: Jin Yao <yao.jin@linux.intel.com>
    Fixes: 1fcd0394 ("perf stat: Update per-thread shadow stats")
    Link: http://lkml.kernel.org/r/20190120191414.12925-1-tonyj@suse.deSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
    Signed-off-by: NSasha Levin <sashal@kernel.org>
    d5f05016
builtin-script.c 91.4 KB