Re: [PATCH net-next v15 11/22] ovpn: implement TCP transport

2024-12-16, 15:09:17 +0100, Antonio Quartulli wrote:

On 16/12/2024 14:59, Sabrina Dubroca wrote:

...

2024-12-11, 22:15:15 +0100, Antonio Quartulli wrote:

...

+static void ovpn_tcp_close(struct sock *sk, long timeout) +{

• struct ovpn_socket *sock;
• rcu_read_lock();

[can't sleep until unlock]

...

• sock = rcu_dereference_sk_user_data(sk);
• strp_stop(&sock->peer->tcp.strp);
• tcp_close(sk, timeout);

 void tcp_close(struct sock *sk, long timeout)
 {
 	lock_sock(sk);

but this can sleep.

Ouch.. I wonder why I have never seen the might_sleep() trigger this, but probably that's due to the fact that we hardly hit this cb in the classic use case.

Probably. You'd only see it when you close the TCP socket before detaching (otherwise the close CB is restored to tcp_close), which I guess ovpn never does.

...

Is there anything that prevents delaying tcp_close until after ovpn_peer_del and rcu_read_unlock?

not really.

...

...

• ovpn_peer_del(sock->peer, OVPN_DEL_PEER_REASON_TRANSPORT_ERROR);
• rcu_read_unlock();

I will move the tcp_close() here.

Thanks.