• Jiri Olsa's avatar
    perf record: Fix crash in pipe mode · cfacbabd
    Jiri Olsa authored
    Currently we can crash perf record when running in pipe mode, like:
    
      $ perf record ls | perf report
      # To display the perf.data header info, please use --header/--header-only options.
      #
      perf: Segmentation fault
      Error:
      The - file has no samples!
    
    The callstack of the crash is:
    
        0x0000000000515242 in perf_event__synthesize_event_update_name
      3513            ev = event_update_event__new(len + 1, PERF_EVENT_UPDATE__NAME, evsel->id[0]);
      (gdb) bt
      #0  0x0000000000515242 in perf_event__synthesize_event_update_name
      #1  0x00000000005158a4 in perf_event__synthesize_extra_attr
      #2  0x0000000000443347 in record__synthesize
      #3  0x00000000004438e3 in __cmd_record
      #4  0x000000000044514e in cmd_record
      #5  0x00000000004cbc95 in run_builtin
      #6  0x00000000004cbf02 in handle_internal_command
      #7  0x00000000004cc054 in run_argv
      #8  0x00000000004cc422 in main
    
    The reason of the crash is that the evsel does not have ids array
    allocated and the pipe's synthesize code tries to access it.
    
    We don't force evsel ids allocation when we have single event, because
    it's not needed. However we need it when we are in pipe mode even for
    single event as a key for evsel update event.
    
    Fixing this by forcing evsel ids allocation event for single event, when
    we are in pipe mode.
    Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
    Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    Cc: David Ahern <dsahern@gmail.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Link: http://lkml.kernel.org/r/20180302161354.30192-1-jolsa@kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    cfacbabd
builtin-record.c 49 KB