diff --git a/mm/damon/core.c b/mm/damon/core.c
index c499a02ac44e..16bedde920f0 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -545,8 +545,27 @@ void damon_destroy_target(struct damon_target *t, struct damon_ctx *ctx)
 	damon_free_target(t);
 }
 
+#ifdef CONFIG_DAMON_DEBUG_SANITY
+static void damon_verify_nr_regions(struct damon_target *t)
+{
+	struct damon_region *r;
+	unsigned int count = 0;
+
+	damon_for_each_region(r, t)
+		count++;
+	WARN_ONCE(count != t->nr_regions, "t->nr_regions (%u) != count (%u)\n",
+			t->nr_regions, count);
+}
+#else
+static void damon_verify_nr_regions(struct damon_target *t)
+{
+}
+#endif
+
 unsigned int damon_nr_regions(struct damon_target *t)
 {
+	damon_verify_nr_regions(t);
+
 	return t->nr_regions;
 }