--- x/net/core/skmsg.c
+++ y/net/core/skmsg.c
@@ -730,6 +730,8 @@ struct sk_psock *sk_psock_init(struct so
 	psock->saved_close = prot->close;
 	psock->saved_write_space = sk->sk_write_space;
 
+	BUG_ON(psock->saved_close == sock_map_close);
+
 	INIT_LIST_HEAD(&psock->link);
 	spin_lock_init(&psock->link_lock);