diff --git a/mm/workingset.c b/mm/workingset.c
index e9f05634747a..6a45e98317e9 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -272,8 +272,13 @@ static bool lru_gen_test_recent(void *shadow, struct lruvec **lruvec,
 	unpack_shadow(shadow, &memcg_id, &pgdat, token, workingset);
 
 	memcg = mem_cgroup_from_id(memcg_id);
+	if (unlikely(!memcg)) {
+		pr_warn("DEBUG: memcg is NULL (memcg_id=%d), pgdat=%p, returning false\n",memcg_id, pgdat);
+		pr_warn("DEBUG: shadow=%p token=%lx workingset=%d\n",shadow, *token, *workingset);
+		return false;
+	}
 	*lruvec = mem_cgroup_lruvec(memcg, pgdat);
-
+	pr_warn("DEBUG: memcg=%p, lruvec=%p, continuing normally\n", memcg, *lruvec);
 	max_seq = READ_ONCE((*lruvec)->lrugen.max_seq);
 	max_seq &= EVICTION_MASK >> LRU_REFS_WIDTH;