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

From: Ian Rogers
Date: Thu Nov 18 2021 - 03:48:11 EST


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@xxxxxxxxxx>
---
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