[PATCH v2 02/25] perf sample: Make sure perf_sample__init/exit are used

Ian Rogers
2026-03-19T23:24:04Z

The deferred stack trace code wasn't using perf_sample__init/exit. Add
the deferred stack trace clean up to perf_sample__exit which requires
proper NULL initialization in perf_sample__init. Make the
perf_sample__exit robust to being called more than once by using
zfree. Make the error paths in evsel__parse_sample exit the sample.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/builtin-inject.c | 5 ++++-
tools/perf/util/evlist.c | 5 ++++-
tools/perf/util/evsel.c | 28 +++++++++++++++++-----------
tools/perf/util/sample.c | 10 ++++++++--
tools/perf/util/session.c | 13 +++++++++----
5 files changed, 42 insertions(+), 19 deletions(-)

diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index 5b29f4296861..039323908ebf 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -1087,6 +1087,7 @@ static int perf_inject__sched_stat(const struct perf_tool *tool,
struct perf_sample sample_sw;
struct perf_inject *inject = container_of(tool, struct perf_inject, tool);
u32 pid = evsel__intval(evsel, sample, "pid");
+ int ret;

list_for_each_entry(ent, &inject->samples, node) {
if (pid == ent->tid)
@@ -1103,7 +1104,9 @@ static int perf_inject__sched_stat(const struct perf_tool *tool,
perf_event__synthesize_sample(event_sw, evsel->core.attr.sample_type,
evsel->core.attr.read_format, &sample_sw);
build_id__mark_dso_hit(tool, event_sw, &sample_sw, evsel, machine);
- return perf_event__repipe(tool, event_sw, &sample_sw, machine);
+ ret = perf_event__repipe(tool, event_sw, &sample_sw, machine);
+ perf_sample__exit(&sample_sw);
+ return ret;
}
#endif

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 591bdf0b3e2a..bdb196425071 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1622,8 +1622,11 @@ int evlist__parse_sample(struct evlist *evlist, union perf_event *event, struct
struct evsel *evsel = evlist__event2evsel(evlist, event);
int ret;

- if (!evsel)
+ if (!evsel) {
+ /* Ensure the sample is okay for perf_sample__exit. */
+ perf_sample__init(sample, /*all=*/false);
return -EFAULT;
+ }
ret = evsel__parse_sample(evsel, event, sample);
if (ret)
return ret;
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index f59228c1a39e..34ae388750db 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -3067,7 +3067,7 @@ static inline bool overflow(const void *endp, u16 max_size, const void *offset,
#define OVERFLOW_CHECK(offset, size, max_size) \
do { \
if (overflow(endp, (max_size), (offset), (size))) \
- return -EFAULT; \
+ goto out_efault; \
} while (0)

#define OVERFLOW_CHECK_u64(offset) \
@@ -3199,6 +3199,8 @@ static int __set_offcpu_sample(struct perf_sample *data)
data->cgroup = *array;

return 0;
+out_efault:
+ return -EFAULT;
}

int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
@@ -3217,7 +3219,7 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
*/
union u64_swap u;

- memset(data, 0, sizeof(*data));
+ perf_sample__init(data, /*all=*/true);
data->cpu = data->pid = data->tid = -1;
data->stream_id = data->id = data->time = -1ULL;
data->period = evsel->core.attr.sample_period;
@@ -3231,25 +3233,26 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,

data->callchain = (struct ip_callchain *)&event->callchain_deferred.nr;
if (data->callchain->nr > max_callchain_nr)
- return -EFAULT;
+ goto out_efault;

data->deferred_cookie = event->callchain_deferred.cookie;

if (evsel->core.attr.sample_id_all)
perf_evsel__parse_id_sample(evsel, event, data);
+
return 0;
}

if (event->header.type != PERF_RECORD_SAMPLE) {
- if (!evsel->core.attr.sample_id_all)
- return 0;
- return perf_evsel__parse_id_sample(evsel, event, data);
+ if (evsel->core.attr.sample_id_all)
+ perf_evsel__parse_id_sample(evsel, event, data);
+ return 0;
}

array = event->sample.array;

if (perf_event__check_size(event, evsel->sample_size))
- return -EFAULT;
+ goto out_efault;

if (type & PERF_SAMPLE_IDENTIFIER) {
data->id = *array;
@@ -3342,7 +3345,7 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
sizeof(struct sample_read_value);

if (data->read.group.nr > max_group_nr)
- return -EFAULT;
+ goto out_efault;

sz = data->read.group.nr * sample_read_value_size(read_format);
OVERFLOW_CHECK(array, sz, max_size);
@@ -3370,7 +3373,7 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
data->callchain = (struct ip_callchain *)array++;
callchain_nr = data->callchain->nr;
if (callchain_nr > max_callchain_nr)
- return -EFAULT;
+ goto out_efault;
sz = callchain_nr * sizeof(u64);
/*
* Save the cookie for the deferred user callchain. The last 2
@@ -3428,7 +3431,7 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
data->branch_stack = (struct branch_stack *)array++;

if (data->branch_stack->nr > max_branch_nr)
- return -EFAULT;
+ goto out_efault;

sz = data->branch_stack->nr * sizeof(struct branch_entry);
if (evsel__has_branch_hw_idx(evsel)) {
@@ -3505,7 +3508,7 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
data->user_stack.size = *array++;
if (WARN_ONCE(data->user_stack.size > sz,
"user stack dump failure\n"))
- return -EFAULT;
+ goto out_efault;
}
}

@@ -3586,6 +3589,9 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
return __set_offcpu_sample(data);

return 0;
+out_efault:
+ perf_sample__exit(data);
+ return -EFAULT;
}

int evsel__parse_sample_timestamp(struct evsel *evsel, union perf_event *event,
diff --git a/tools/perf/util/sample.c b/tools/perf/util/sample.c
index 8f82aaf1aab6..b04cbad7edd3 100644
--- a/tools/perf/util/sample.c
+++ b/tools/perf/util/sample.c
@@ -21,13 +21,19 @@ void perf_sample__init(struct perf_sample *sample, bool all)
} else {
sample->user_regs = NULL;
sample->intr_regs = NULL;
+ sample->deferred_callchain = false;
+ sample->callchain = NULL;
}
}

void perf_sample__exit(struct perf_sample *sample)
{
- free(sample->user_regs);
- free(sample->intr_regs);
+ zfree(&sample->user_regs);
+ zfree(&sample->intr_regs);
+ if (sample->deferred_callchain) {
+ zfree(&sample->callchain);
+ sample->deferred_callchain = false;
+ }
}

struct regs_dump *perf_sample__user_regs(struct perf_sample *sample)
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 4b465abfa36c..c48e840da7d4 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1367,14 +1367,18 @@ static int evlist__deliver_deferred_callchain(struct evlist *evlist,
list_for_each_entry_safe(de, tmp, &evlist->deferred_samples, list) {
struct perf_sample orig_sample;

+ perf_sample__init(&orig_sample, /*all=*/false);
ret = evlist__parse_sample(evlist, de->event, &orig_sample);
if (ret < 0) {
pr_err("failed to parse original sample\n");
+ perf_sample__exit(&orig_sample);
break;
}

- if (sample->tid != orig_sample.tid)
+ if (sample->tid != orig_sample.tid) {
+ perf_sample__exit(&orig_sample);
continue;
+ }

if (event->callchain_deferred.cookie == orig_sample.deferred_cookie)
sample__merge_deferred_callchain(&orig_sample, sample);
@@ -1385,9 +1389,7 @@ static int evlist__deliver_deferred_callchain(struct evlist *evlist,
ret = evlist__deliver_sample(evlist, tool, de->event,
&orig_sample, evsel, machine);

- if (orig_sample.deferred_callchain)
- free(orig_sample.callchain);
-
+ perf_sample__exit(&orig_sample);
list_del(&de->list);
free(de->event);
free(de);
@@ -1414,9 +1416,11 @@ static int session__flush_deferred_samples(struct perf_session *session,
list_for_each_entry_safe(de, tmp, &evlist->deferred_samples, list) {
struct perf_sample sample;

+ perf_sample__init(&sample, /*all=*/false);
ret = evlist__parse_sample(evlist, de->event, &sample);
if (ret < 0) {
pr_err("failed to parse original sample\n");
+ perf_sample__exit(&sample);
break;
}

@@ -1424,6 +1428,7 @@ static int session__flush_deferred_samples(struct perf_session *session,
ret = evlist__deliver_sample(evlist, tool, de->event,
&sample, evsel, machine);

+ perf_sample__exit(&sample);
list_del(&de->list);
free(de->event);
free(de);
--
2.53.0.959.g497ff81fa9-goog