Re: [syzbot] [mm?] [f2fs?] [exfat?] memory leak in __kfree_rcu_sheaf

Catalin Marinas
2026-03-08T11:04:11Z

#syz test

diff --git a/mm/slab_common.c b/mm/slab_common.c
index d5a70a831a2a..73f4668d870d 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1954,8 +1954,14 @@ void kvfree_call_rcu(struct rcu_head *head, void *ptr)
if (!head)
might_sleep();

- if (!IS_ENABLED(CONFIG_PREEMPT_RT) && kfree_rcu_sheaf(ptr))
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT) && kfree_rcu_sheaf(ptr)) {
+ /*
+ * The object is now queued for deferred freeing via an RCU
+ * sheaf. Tell kmemleak to ignore it.
+ */
+ kmemleak_ignore(ptr);
return;
+ }

// Queue the object but don't yet schedule the batch.
if (debug_rcu_head_queue(ptr)) {