releases/6.15.10/perf-sched-fix-memory-leaks-in-perf-sched-latency.patch

From 71b5346b6b4e67a86be68fbbcd7d3d3841271957 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Wed, 2 Jul 2025 18:49:41 -0700
Subject: perf sched: Fix memory leaks in 'perf sched latency'

From: Namhyung Kim <namhyung@kernel.org>

[ Upstream commit e68b1c0098b959cb88afce5c93dd6a9324e6da78 ]

The work_atoms should be freed after use.  Add free_work_atoms() to
make sure to release all.  It should use list_splice_init() when merging
atoms to prevent accessing invalid pointers.

Fixes: b1ffe8f3e0c96f552 ("perf sched: Finish latency => atom rename and misc cleanups")
Reviewed-by: Ian Rogers <irogers@google.com>
Tested-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250703014942.1369397-8-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/perf/builtin-sched.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 087d4eaba5f7..4bbebd6ef2e4 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -1111,6 +1111,21 @@ add_sched_in_event(struct work_atoms *atoms, u64 timestamp)
 	atoms->nb_atoms++;
 }
 
+static void free_work_atoms(struct work_atoms *atoms)
+{
+	struct work_atom *atom, *tmp;
+
+	if (atoms == NULL)
+		return;
+
+	list_for_each_entry_safe(atom, tmp, &atoms->work_list, list) {
+		list_del(&atom->list);
+		free(atom);
+	}
+	thread__zput(atoms->thread);
+	free(atoms);
+}
+
 static int latency_switch_event(struct perf_sched *sched,
 				struct evsel *evsel,
 				struct perf_sample *sample,
@@ -3426,13 +3441,13 @@ static void __merge_work_atoms(struct rb_root_cached *root, struct work_atoms *d
 			this->total_runtime += data->total_runtime;
 			this->nb_atoms += data->nb_atoms;
 			this->total_lat += data->total_lat;
-			list_splice(&data->work_list, &this->work_list);
+			list_splice_init(&data->work_list, &this->work_list);
 			if (this->max_lat < data->max_lat) {
 				this->max_lat = data->max_lat;
 				this->max_lat_start = data->max_lat_start;
 				this->max_lat_end = data->max_lat_end;
 			}
-			zfree(&data);
+			free_work_atoms(data);
 			return;
 		}
 	}
@@ -3511,7 +3526,6 @@ static int perf_sched__lat(struct perf_sched *sched)
 		work_list = rb_entry(next, struct work_atoms, node);
 		output_lat_thread(sched, work_list);
 		next = rb_next(next);
-		thread__zput(work_list->thread);
 	}
 
 	printf(" -----------------------------------------------------------------------------------------------------------------\n");
@@ -3525,6 +3539,13 @@ static int perf_sched__lat(struct perf_sched *sched)
 
 	rc = 0;
 
+	while ((next = rb_first_cached(&sched->sorted_atom_root))) {
+		struct work_atoms *data;
+
+		data = rb_entry(next, struct work_atoms, node);
+		rb_erase_cached(next, &sched->sorted_atom_root);
+		free_work_atoms(data);
+	}
 out_free_cpus_switch_event:
 	free_cpus_switch_event(sched);
 	return rc;
-- 
2.39.5