perf probe: Fix event namelist to duplicate string

Fix event namelist to duplicate string. Without duplicating, adding
multiple probes causes stack overwrite bug, because it reuses a
buffer on stack while the buffer is already added in the namelist.
String duplication solves this bug because only contents of the
buffer is copied to the namelist.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091207170046.19230.55557.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/util/probe-event.c

@@ -413,12 +413,13 @@ static struct strlist *get_perf_event_names(int fd)
 
 	rawlist = get_trace_kprobe_event_rawlist(fd);
 
-	sl = strlist__new(false, NULL);
+	sl = strlist__new(true, NULL);
 	for (i = 0; i < strlist__nr_entries(rawlist); i++) {
 		ent = strlist__entry(rawlist, i);
 		parse_trace_kprobe_event(ent->s, &group, &event, NULL);
 		strlist__add(sl, event);
 		free(group);
+		free(event);
 	}
 
 	strlist__delete(rawlist);
@@ -480,5 +481,6 @@ void add_trace_kprobe_events(struct probe_point *probes, int nr_probes)
 			strlist__add(namelist, event);
 		}
 	}
+	strlist__delete(namelist);
 	close(fd);
 }