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

[Harry Yoo]

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index d79acf5c5100..b401954f72a4 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -107,7 +107,7 @@
  * Kmemleak configuration and common defines.
  */
 #define MAX_TRACE		16	/* stack trace length */
-#define MSECS_MIN_AGE		5000	/* minimum object age for reporting */
+#define MSECS_MIN_AGE		30000	/* minimum object age for reporting */
 #define SECS_FIRST_SCAN		60	/* delay before the first scan */
 #define SECS_SCAN_WAIT		600	/* subsequent auto scanning delay */
 #define MAX_SCAN_SIZE		4096	/* maximum size of a scanned block */
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)) {
diff --git a/mm/slub.c b/mm/slub.c
index 20cb4f3b636d..6bdf409d427e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -7537,6 +7537,7 @@ static void early_kmem_cache_node_alloc(int node)
 	n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL, false);
 	slab->freelist = get_freepointer(kmem_cache_node, n);
 	slab->inuse = 1;
+	kmemleak_alloc(n, sizeof(*n), 1, GFP_NOWAIT);
 	kmem_cache_node->node[node] = n;
 	init_kmem_cache_node(n, NULL);
 	inc_slabs_node(kmem_cache_node, node, slab->objects);