diff --git a/mm/slob.c b/mm/slob.c
index f729c46..3d73b3b 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -554,7 +554,7 @@
 					    flags, node);
 	}
 
-	if (c->ctor)
+	if (b && c->ctor)
 		c->ctor(b);
 
 	kmemleak_alloc_recursive(b, c->size, 1, c->flags, flags);