Hello, Steven.
Can you please see whether the following patch makes the lockdep
warning go away?
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 07ef550c6627..93315d6b21a8 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -84,6 +84,7 @@ struct kmem_cache {
int red_left_pad; /* Left redzone padding size */
#ifdef CONFIG_SYSFS
struct kobject kobj; /* For sysfs */
+ struct work_struct kobj_remove_work;
#endif
#ifdef CONFIG_MEMCG
struct memcg_cache_params memcg_params;
diff --git a/mm/slub.c b/mm/slub.c
index 7449593fca72..8addc535bcdc 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5625,6 +5625,28 @@ static char *create_unique_id(struct kmem_cache *s)
return name;
}
+static void sysfs_slab_remove_workfn(struct work_struct *work)
+{
+ struct kmem_cache *s =
+ container_of(work, struct kmem_cache, kobj_remove_work);
+
+ if (!s->kobj.state_in_sysfs)
+ /*
+ * For a memcg cache, this may be called during
+ * deactivation and again on shutdown. Remove only once.
+ * A cache is never shut down before deactivation is
+ * complete, so no need to worry about synchronization.
+ */
+ return;
+
+#ifdef CONFIG_MEMCG
+ kset_unregister(s->memcg_kset);
+#endif
+ kobject_uevent(&s->kobj, KOBJ_REMOVE);
+ kobject_del(&s->kobj);
+ kobject_put(&s->kobj);
+}
+
static int sysfs_slab_add(struct kmem_cache *s)
{
int err;
@@ -5632,6 +5654,8 @@ static int sysfs_slab_add(struct kmem_cache *s)
struct kset *kset = cache_kset(s);
int unmergeable = slab_unmergeable(s);
+ INIT_WORK(&s->kobj_remove_work, sysfs_slab_remove_workfn);
+
if (!kset) {
kobject_init(&s->kobj, &slab_ktype);
return 0;
@@ -5695,20 +5719,8 @@ static void sysfs_slab_remove(struct kmem_cache *s)
*/
return;
- if (!s->kobj.state_in_sysfs)
- /*
- * For a memcg cache, this may be called during
- * deactivation and again on shutdown. Remove only once.
- * A cache is never shut down before deactivation is
- * complete, so no need to worry about synchronization.
- */
- return;
-
-#ifdef CONFIG_MEMCG
- kset_unregister(s->memcg_kset);
-#endif
- kobject_uevent(&s->kobj, KOBJ_REMOVE);
- kobject_del(&s->kobj);
+ kobject_get(&s->kobj);
+ schedule_work(&s->kobj_remove_work);
}
void sysfs_slab_release(struct kmem_cache *s)
