perf header: Set tracepoint event name only if not set

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.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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;
 	}