perf tools: Use zfree() to avoid keeping dangling pointers

The cases changed in this patch are for when we free but keep the
pointer to the freed area, which is not always a good idea.

Be more defensive and zero the pointer to avoid possible use after
free bugs to take more time to be detected.

Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1485952447-7013-5-git-send-email-treeze.taeung@gmail.com
[ rewrote commit log ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/parse-events.c

@@ -1479,7 +1479,7 @@ static void perf_pmu__parse_cleanup(void)
 
 		for (i = 0; i < perf_pmu_events_list_num; i++) {
 			p = perf_pmu_events_list + i;
-			free(p->symbol);
+			zfree(&p->symbol);
 		}
 		zfree(&perf_pmu_events_list);
 		perf_pmu_events_list_num = 0;
@@ -1570,7 +1570,7 @@ perf_pmu__parse_check(const char *name)
 	r = bsearch(&p, perf_pmu_events_list,
 			(size_t) perf_pmu_events_list_num,
 			sizeof(struct perf_pmu_event_symbol), comp_pmu);
-	free(p.symbol);
+	zfree(&p.symbol);
 	return r ? r->type : PMU_EVENT_SYMBOL_ERR;
 }
 
@@ -1717,8 +1717,8 @@ static void parse_events_print_error(struct parse_events_error *err,
 		fprintf(stderr, "%*s\\___ %s\n", idx + 1, "", err->str);
 		if (err->help)
 			fprintf(stderr, "\n%s\n", err->help);
-		free(err->str);
-		free(err->help);
+		zfree(&err->str);
+		zfree(&err->help);
 	}
 
 	fprintf(stderr, "Run 'perf list' for a list of valid events\n");
@@ -2413,7 +2413,7 @@ void parse_events_terms__purge(struct list_head *terms)
 
 	list_for_each_entry_safe(term, h, terms, list) {
 		if (term->array.nr_ranges)
-			free(term->array.ranges);
+			zfree(&term->array.ranges);
 		list_del_init(&term->list);
 		free(term);
 	}
@@ -2429,7 +2429,7 @@ void parse_events_terms__delete(struct list_head *terms)
 
 void parse_events__clear_array(struct parse_events_array *a)
 {
-	free(a->ranges);
+	zfree(&a->ranges);
 }
 
 void parse_events_evlist_error(struct parse_events_evlist *data,