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

[Catalin Marinas]

#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)) {