[PATCH] mm/damon/stat: deallocate damon_call() failure leaking damon_ctx

[SeongJae Park <sj@kernel.org>]

DAMON_STAT does not deallocate its dynamically allocated damon_ctx
object when damon_call() is failed.  As a result, the memory is leaked.
Check the failure and deallocate the damon_ctx object.

The issue was discovered [1] by sashiko.

[1] https://lore.kernel.org/20260401012428.86694-1-sj@kernel.org

Fixes: 405f61996d9d ("mm/damon/stat: use damon_call() repeat mode instead of damon_callback")
Cc: <stable@vger.kernel.org> # 6.17.x
Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/stat.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/mm/damon/stat.c b/mm/damon/stat.c
index 5a742fc157e4..30aeb2c207ec 100644
--- a/mm/damon/stat.c
+++ b/mm/damon/stat.c
@@ -257,7 +257,12 @@ static int damon_stat_start(void)
 
 	damon_stat_last_refresh_jiffies = jiffies;
 	call_control.data = damon_stat_context;
-	return damon_call(damon_stat_context, &call_control);
+	err = damon_call(damon_stat_context, &call_control);
+	if (err) {
+		damon_destroy_ctx(damon_stat_context);
+		damon_stat_context = NULL;
+	}
+	return err;
 }
 
 static void damon_stat_stop(void)

base-commit: 4fd04f750d79667937931314ed64c9d79b0d82ef
-- 
2.47.3