@@ -649,6 +649,11 @@ static void disarm_kmem_keys(struct mem_cgroup *memcg)
 {
 	if (test_bit(KMEM_ACCOUNTED_THIS, &memcg->kmem_accounted))
 		static_key_slow_dec(&memcg_kmem_enabled_key);
+	/*
+	 * This check can't live in kmem destruction function,
+	 * since the charges will outlive the cgroup
+	 */
+	WARN_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0);
 }
 #else
 static void disarm_kmem_keys(struct mem_cgroup *memcg)

@@ -4005,6 +4010,7 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg, bool free_all)
 	int node, zid, shrink;
 	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
 	struct cgroup *cgrp = memcg->css.cgroup;
+	u64 usage;
 
 	css_get(&memcg->css);
 

@@ -4038,8 +4044,17 @@ move_account:
 		mem_cgroup_end_move(memcg);
 		memcg_oom_recover(memcg);
 		cond_resched();
+		/*
+		 * Kernel memory may not necessarily be trackable to a specific
+		 * process. So they are not migrated, and therefore we can't
+		 * expect their value to drop to 0 here.
+		 *
+		 * having res filled up with kmem only is enough
+		 */
+		usage = res_counter_read_u64(&memcg->res, RES_USAGE) -
+			res_counter_read_u64(&memcg->kmem, RES_USAGE);
 	/* "ret" should also be checked to ensure all lists are empty. */
-	} while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0 || ret);
+	} while (usage > 0 || ret);
 out:
 	css_put(&memcg->css);
 	return ret;