2024-11-12, 15:26:59 +0100, Antonio Quartulli wrote:
On 11/11/2024 16:41, Sabrina Dubroca wrote:
2024-10-29, 11:47:31 +0100, Antonio Quartulli wrote:
+void ovpn_peer_hash_vpn_ip(struct ovpn_peer *peer)
- __must_hold(&peer->ovpn->peers->lock)
Changes to peer->vpn_addrs are not protected by peers->lock, so those could be getting updated while we're rehashing (and taking peer->lock in ovpn_nl_peer_modify as I'm suggesting above also wouldn't prevent that).
/me screams :-D
Sorry :)
Indeed peers->lock is only about protecting the lists, not the content of the listed objects.
How about acquiring the peers->lock before calling ovpn_nl_peer_modify()?
It seems like it would work. Maybe a bit weird to have conditional locking (MP mode only), but ok. You already have this lock ordering (hold peers->lock before taking peer->lock) in ovpn_peer_keepalive_work_mp, so there should be no deadlock from doing the same thing in the netlink code.
Then I would also do that in ovpn_peer_float to protect that rehash.
It feels like peers->lock is turning into a duplicate of ovpn->lock. ovpn->lock used for P2P mode, peers->lock used equivalently for MP mode. You might consider merging them (but I wouldn't see it as necessary for merging the series unless there's a locking issue with the current proposal).