diff --git a/mm/util.c b/mm/util.c
index 18396ea..f2f21b7 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -76,7 +76,7 @@
 
 	if (unlikely(!new_size)) {
 		kfree(p);
-		return NULL;
+		return ZERO_SIZE_PTR;
 	}
 
 	ks = ksize(p);