Re: [syzbot] [bpf?] [net?] WARNING in sock_map_close (2)

[Hillf Danton]

On Thu, 22 Aug 2024 06:19:27 -0700
> syzbot found the following issue on:
> 
> HEAD commit:    d785ed945de6 net: wwan: t7xx: PCIe reset rescan
> git tree:       net-next
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12378c33980000

#syz test net-next  d785ed945de6

--- x/net/core/sock_map.c
+++ y/net/core/sock_map.c
@@ -196,7 +196,7 @@ static void sock_map_unref(struct sock *
 
 static int sock_map_init_proto(struct sock *sk, struct sk_psock *psock)
 {
-	if (!sk->sk_prot->psock_update_sk_prot)
+	if (!sk->sk_prot->psock_update_sk_prot || psock->saved_close == sock_map_close)
 		return -EINVAL;
 	psock->psock_update_sk_prot = sk->sk_prot->psock_update_sk_prot;
 	return sk->sk_prot->psock_update_sk_prot(sk, psock, false);
--