perf metrics: Copy entire pmu_event in find metric

The pmu_event passed to the pmu_events_table_for_each_event is invalid
after the loop. Copy the entire struct in metricgroup__find_metric.
Reduce the scope of this function to static.

Signed-off-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Garry <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Xing Zhengjun <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

tools/perf/util/metricgroup.c

@@ -879,6 +879,10 @@ struct metricgroup_add_iter_data {
 	const struct pmu_events_table *table;
 };
 
+static bool metricgroup__find_metric(const char *metric,
+				     const struct pmu_events_table *table,
+				     struct pmu_event *pe);
+
 static int add_metric(struct list_head *metric_list,
 		      const struct pmu_event *pe,
 		      const char *modifier,
@@ -914,7 +918,7 @@ static int resolve_metric(struct list_head *metric_list,
 	size_t bkt;
 	struct to_resolve {
 		/* The metric to resolve. */
-		const struct pmu_event *pe;
+		struct pmu_event pe;
 		/*
 		 * The key in the IDs map, this may differ from in case,
 		 * etc. from pe->metric_name.
@@ -928,16 +932,15 @@ static int resolve_metric(struct list_head *metric_list,
 	 * the pending array.
 	 */
 	hashmap__for_each_entry(root_metric->pctx->ids, cur, bkt) {
-		const struct pmu_event *pe;
+		struct pmu_event pe;
 
-		pe = metricgroup__find_metric(cur->key, table);
-		if (pe) {
+		if (metricgroup__find_metric(cur->key, table, &pe)) {
 			pending = realloc(pending,
 					(pending_cnt + 1) * sizeof(struct to_resolve));
 			if (!pending)
 				return -ENOMEM;
 
-			pending[pending_cnt].pe = pe;
+			memcpy(&pending[pending_cnt].pe, &pe, sizeof(pe));
 			pending[pending_cnt].key = cur->key;
 			pending_cnt++;
 		}
@@ -952,7 +955,7 @@ static int resolve_metric(struct list_head *metric_list,
 	 * context.
 	 */
 	for (i = 0; i < pending_cnt; i++) {
-		ret = add_metric(metric_list, pending[i].pe, modifier, metric_no_group,
+		ret = add_metric(metric_list, &pending[i].pe, modifier, metric_no_group,
 				root_metric, visited, table);
 		if (ret)
 			break;
@@ -1073,7 +1076,7 @@ static int __add_metric(struct list_head *metric_list,
 
 struct metricgroup__find_metric_data {
 	const char *metric;
-	const struct pmu_event *pe;
+	struct pmu_event *pe;
 };
 
 static int metricgroup__find_metric_callback(const struct pmu_event *pe,
@@ -1085,21 +1088,21 @@ static int metricgroup__find_metric_callback(const struct pmu_event *pe,
 	if (!match_metric(pe->metric_name, data->metric))
 		return 0;
 
-	data->pe = pe;
-	return -1;
+	memcpy(data->pe, pe, sizeof(*pe));
+	return 1;
 }
 
-const struct pmu_event *metricgroup__find_metric(const char *metric,
-						 const struct pmu_events_table *table)
+static bool metricgroup__find_metric(const char *metric,
+				     const struct pmu_events_table *table,
+				     struct pmu_event *pe)
 {
 	struct metricgroup__find_metric_data data = {
 		.metric = metric,
-		.pe = NULL,
+		.pe = pe,
 	};
 
-	pmu_events_table_for_each_event(table, metricgroup__find_metric_callback, &data);
-
-	return data.pe;
+	return pmu_events_table_for_each_event(table, metricgroup__find_metric_callback, &data)
+		? true : false;
 }
 
 static int add_metric(struct list_head *metric_list,

tools/perf/util/metricgroup.h

@@ -69,8 +69,6 @@ int metricgroup__parse_groups(const struct option *opt,
 			      bool metric_no_group,
 			      bool metric_no_merge,
 			      struct rblist *metric_events);
-const struct pmu_event *metricgroup__find_metric(const char *metric,
-						 const struct pmu_events_table *table);
 int metricgroup__parse_groups_test(struct evlist *evlist,
 				   const struct pmu_events_table *table,
 				   const char *str,