Re: [PATCH 14/17] perf header: Set tracepoint event name only if not set

[David Ahern <dsahern@gmail.com>]

On 9/5/12 5:08 PM, Arnaldo Carvalho de Melo wrote:
> From: Namhyung Kim <namhyung.kim@lge.com>
>
> The event name can be set already by processing a event_desc data.
>
> So check it before setting to prevent possible leak.
>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Link: http://lkml.kernel.org/r/1346821373-31621-3-git-send-email-namhyung@kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
>   tools/perf/util/header.c |    2 +-
>   1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index a124b93..05c9310 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -2314,7 +2314,7 @@ static int perf_evlist__set_tracepoint_names(struct perf_evlist *evlist,
>   	struct perf_evsel *pos;
>
>   	list_for_each_entry(pos, &evlist->entries, node) {
> -		if (pos->attr.type == PERF_TYPE_TRACEPOINT &&
> +		if (pos->attr.type == PERF_TYPE_TRACEPOINT && !pos->name &&
>   		    perf_evsel__set_tracepoint_name(pos, pevent))
>   			return -1;
>   	}
>

I'm getting a segfault running perf-script due to this patch. Most 
likely this is exposing another problem. Back trace is:

#0  0x000000000049f4f2 in pevent_event_info (s=0x7fffffffdab0, 
event=0x0, record=0x7fffffffda70)
     at tools/lib/traceevent/event-parse.c:4183
#1  0x000000000046cd52 in event_format__print (event=0x0, cpu=<optimized 
out>, data=<optimized out>, size=<optimized out>)
     at util/trace-event-parse.c:182
#2  0x000000000042d41b in process_event (event=0x7fffef9d1e60, 
sample=0x7fffffffdc90, evsel=0x90d870, machine=0x906f80,
     al=<optimized out>) at builtin-script.c:415
#3  0x000000000042c4e1 in process_sample_event (tool=<optimized out>, 
event=0x7fffef9d1e60, sample=0x7fffffffdc90, evsel=
     0x90d870, machine=0x906f80) at builtin-script.c:515
#4  0x000000000046864d in perf_session_deliver_event (session=<optimized 
out>, event=0x7fffef9d1e60, sample=0x7fffffffdc90,
     tool=0x79d020, file_offset=<optimized out>) at util/session.c:1065
#5  0x0000000000468c5a in flush_sample_queue (s=0x906f20, tool=0x79d020) 
at util/session.c:719
#6  0x0000000000468d46 in process_finished_round (tool=<optimized out>, 
event=<optimized out>, session=0x906f20)
     at util/session.c:790
#7  0x0000000000469055 in perf_session__process_user_event 
(file_offset=541768, tool=0x79d020, event=0x7fffefa2b448,
     session=0x906f20) at util/session.c:1129
#8  perf_session__process_event (session=0x906f20, event=0x7fffefa2b448, 
tool=0x79d020, file_offset=541768)
     at util/session.c:1161
#9  0x000000000046a851 in __perf_session__process_events 
(session=0x906f20, data_offset=<optimized out>,
     data_size=<optimized out>, file_size=2564784, tool=0x79d020) at 
util/session.c:1429
#10 0x000000000042ebdc in __cmd_script (session=0x906f20) at 
builtin-script.c:548