slub: release kobject if sysfs_create_group failed in sysfs_slab_add

When CONFIG_SLUB_DEBUG is enabled, sysfs_slab_add should unlink and put the
kobject if sysfs_create_group failed. Otherwise, sysfs_slab_add returns error
then free kmem_cache s, thus memory of s->kobj is leaked.
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

mm/slub.c

@@ -4593,8 +4593,11 @@ static int sysfs_slab_add(struct kmem_cache *s)
 	}
 
 	err = sysfs_create_group(&s->kobj, &slab_attr_group);
-	if (err)
+	if (err) {
+		kobject_del(&s->kobj);
+		kobject_put(&s->kobj);
 		return err;
+	}
 	kobject_uevent(&s->kobj, KOBJ_ADD);
 	if (!unmergeable) {
 		/* Setup first alias */