diff --git a/mm/slab_common.c b/mm/slab_common.c
index 989784b..6087b1f 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -488,6 +488,7 @@
 			     struct kmem_cache *root_cache)
 {
 	static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */
+	struct cgroup_subsys_state *css = mem_cgroup_css(memcg);
 	struct memcg_cache_array *arr;
 	struct kmem_cache *s = NULL;
 	char *cache_name;
@@ -510,10 +511,9 @@
 	if (arr->entries[idx])
 		goto out_unlock;
 
-	cgroup_name(mem_cgroup_css(memcg)->cgroup,
-		    memcg_name_buf, sizeof(memcg_name_buf));
+	cgroup_name(css->cgroup, memcg_name_buf, sizeof(memcg_name_buf));
 	cache_name = kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name,
-			       idx, memcg_name_buf);
+			       css->id, memcg_name_buf);
 	if (!cache_name)
 		goto out_unlock;