[PATCH 6.19 52/86] mm/damon/sysfs: dealloc repeat_call_control if damon_call() fails

Greg Kroah-Hartman
2026-04-13T16:05:21Z

From: SeongJae Park <sj@kernel.org>

commit 0199390a6b92fc21860e1b858abf525c7e73b956 upstream.

damon_call() for repeat_call_control of DAMON_SYSFS could fail if somehow
the kdamond is stopped before the damon_call(). It could happen, for
example, when te damon context was made for monitroing of a virtual
address processes, and the process is terminated immediately, before the
damon_call() invocation. In the case, the dyanmically allocated
repeat_call_control is not deallocated and leaked.

Fix the leak by deallocating the repeat_call_control under the
damon_call() failure.

This issue is discovered by sashiko [1].

Link: https://lkml.kernel.org/r/20260327003224.55752-1-sj@kernel.org
Link: https://lore.kernel.org/20260320020630.962-1-sj@kernel.org [1]
Fixes: 04a06b139ec0 ("mm/damon/sysfs: use dynamically allocated repeat mode damon_call_control")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [6.17+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
mm/damon/sysfs.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1673,7 +1673,8 @@ static int damon_sysfs_turn_damon_on(str
repeat_call_control->data = kdamond;
repeat_call_control->repeat = true;
repeat_call_control->dealloc_on_cancel = true;
- damon_call(ctx, repeat_call_control);
+ if (damon_call(ctx, repeat_call_control))
+ kfree(repeat_call_control);
return err;
}