--- x/net/core/skmsg.c
+++ y/net/core/skmsg.c
@@ -728,6 +728,7 @@ struct sk_psock *sk_psock_init(struct so
 	psock->saved_unhash = prot->unhash;
 	psock->saved_destroy = prot->destroy;
 	psock->saved_close = prot->close;
+	BUG_ON(psock->saved_close == sock_map_close);
 	psock->saved_write_space = sk->sk_write_space;
 
 	INIT_LIST_HEAD(&psock->link);