[PATCH] perf evsel: Fix memory leaks relating to unit

* [PATCH] perf evsel: Fix memory leaks relating to unit
@ 2021-11-18  8:47 Ian Rogers
  2021-11-18 13:19 ` Arnaldo Carvalho de Melo
  0 siblings, 1 reply; 2+ messages in thread
From: Ian Rogers @ 2021-11-18  8:47 UTC (permalink / raw)
  To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
	Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
	linux-perf-users, linux-kernel
  Cc: Stephane Eranian, Ian Rogers

unit may have a strdup pointer or be to a literal, consequently memory
assocciated with it isn't freed. Change it so the unit is always strdup
and so the memory can be safely freed. Fix related issue in
perf_event__process_event_update for name and own_cpus. Leaks were
spotted by leak sanitizer.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/event_update.c |  5 ++---
 tools/perf/util/evsel.c         | 18 +++++++++---------
 tools/perf/util/header.c        |  8 +++++---
 tools/perf/util/parse-events.c  |  9 ++++++---
 4 files changed, 22 insertions(+), 18 deletions(-)

diff --git a/tools/perf/tests/event_update.c b/tools/perf/tests/event_update.c
index fbb68deba59f..d01532d40acb 100644
--- a/tools/perf/tests/event_update.c
+++ b/tools/perf/tests/event_update.c
@@ -88,7 +88,6 @@ static int test__event_update(struct test_suite *test __maybe_unused, int subtes
 	struct evsel *evsel;
 	struct event_name tmp;
 	struct evlist *evlist = evlist__new_default();
-	char *unit = strdup("KRAVA");
 
 	TEST_ASSERT_VAL("failed to get evlist", evlist);
 
@@ -99,7 +98,8 @@ static int test__event_update(struct test_suite *test __maybe_unused, int subtes
 
 	perf_evlist__id_add(&evlist->core, &evsel->core, 0, 0, 123);
 
-	evsel->unit = unit;
+	free((char *)evsel->unit);
+	evsel->unit = strdup("KRAVA");
 
 	TEST_ASSERT_VAL("failed to synthesize attr update unit",
 			!perf_event__synthesize_event_update_unit(NULL, evsel, process_event_unit));
@@ -119,7 +119,6 @@ static int test__event_update(struct test_suite *test __maybe_unused, int subtes
 	TEST_ASSERT_VAL("failed to synthesize attr update cpus",
 			!perf_event__synthesize_event_update_cpus(&tmp.tool, evsel, process_event_cpus));
 
-	free(unit);
 	evlist__delete(evlist);
 	return 0;
 }
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index a59fb2ecb84e..ac0127be0459 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -241,7 +241,7 @@ void evsel__init(struct evsel *evsel,
 {
 	perf_evsel__init(&evsel->core, attr, idx);
 	evsel->tracking	   = !idx;
-	evsel->unit	   = "";
+	evsel->unit	   = strdup("");
 	evsel->scale	   = 1.0;
 	evsel->max_events  = ULONG_MAX;
 	evsel->evlist	   = NULL;
@@ -276,13 +276,8 @@ struct evsel *evsel__new_idx(struct perf_event_attr *attr, int idx)
 	}
 
 	if (evsel__is_clock(evsel)) {
-		/*
-		 * The evsel->unit points to static alias->unit
-		 * so it's ok to use static string in here.
-		 */
-		static const char *unit = "msec";
-
-		evsel->unit = unit;
+		free((char *)evsel->unit);
+		evsel->unit = strdup("msec");
 		evsel->scale = 1e-6;
 	}
 
@@ -420,7 +415,11 @@ struct evsel *evsel__clone(struct evsel *orig)
 
 	evsel->max_events = orig->max_events;
 	evsel->tool_event = orig->tool_event;
-	evsel->unit = orig->unit;
+	free((char *)evsel->unit);
+	evsel->unit = strdup(orig->unit);
+	if (evsel->unit == NULL)
+		goto out_err;
+
 	evsel->scale = orig->scale;
 	evsel->snapshot = orig->snapshot;
 	evsel->per_pkg = orig->per_pkg;
@@ -1441,6 +1440,7 @@ void evsel__exit(struct evsel *evsel)
 	zfree(&evsel->group_name);
 	zfree(&evsel->name);
 	zfree(&evsel->pmu_name);
+	zfree(&evsel->unit);
 	zfree(&evsel->metric_id);
 	evsel__zero_per_pkg(evsel);
 	hashmap__free(evsel->per_pkg_mask);
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index fda8d14c891f..79cce216727e 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -4257,9 +4257,11 @@ int perf_event__process_event_update(struct perf_tool *tool __maybe_unused,
 
 	switch (ev->type) {
 	case PERF_EVENT_UPDATE__UNIT:
+		free((char *)evsel->unit);
 		evsel->unit = strdup(ev->data);
 		break;
 	case PERF_EVENT_UPDATE__NAME:
+		free(evsel->name);
 		evsel->name = strdup(ev->data);
 		break;
 	case PERF_EVENT_UPDATE__SCALE:
@@ -4268,11 +4270,11 @@ int perf_event__process_event_update(struct perf_tool *tool __maybe_unused,
 		break;
 	case PERF_EVENT_UPDATE__CPUS:
 		ev_cpus = (struct perf_record_event_update_cpus *)ev->data;
-
 		map = cpu_map__new_data(&ev_cpus->cpus);
-		if (map)
+		if (map) {
+			perf_cpu_map__put(evsel->core.own_cpus);
 			evsel->core.own_cpus = map;
-		else
+		} else
 			pr_err("failed to get event_update cpus\n");
 	default:
 		break;
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index a2f4c086986f..12d925a6d27f 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -402,8 +402,10 @@ static int add_event_tool(struct list_head *list, int *idx,
 	if (!evsel)
 		return -ENOMEM;
 	evsel->tool_event = tool_event;
-	if (tool_event == PERF_TOOL_DURATION_TIME)
-		evsel->unit = "ns";
+	if (tool_event == PERF_TOOL_DURATION_TIME) {
+		free((char *)evsel->unit);
+		evsel->unit = strdup("ns");
+	}
 	return 0;
 }
 
@@ -1630,7 +1632,8 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
 	if (parse_state->fake_pmu)
 		return 0;
 
-	evsel->unit = info.unit;
+	free((char *)evsel->unit);
+	evsel->unit = strdup(info.unit);
 	evsel->scale = info.scale;
 	evsel->per_pkg = info.per_pkg;
 	evsel->snapshot = info.snapshot;
-- 
2.34.0.rc1.387.gb447b232ab-goog


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