Re: [PATCH net] net: lockless sock_i_ino()

[Andrei Vagin <avagin@google.com>]

On Tue, Sep 02, 2025 at 06:36:03PM +0000, Eric Dumazet wrote:
> @@ -2056,6 +2058,10 @@ static inline int sk_rx_queue_get(const struct sock *sk)
>  static inline void sk_set_socket(struct sock *sk, struct socket *sock)
>  {
>  	sk->sk_socket = sock;
> +	if (sock) {
> +		WRITE_ONCE(sk->sk_uid, SOCK_INODE(sock)->i_uid);
> +		WRITE_ONCE(sk->sk_ino, SOCK_INODE(sock)->i_ino);
> +	}

Hi Eric.

This change breaks CRIU [1]. The issue is that socket_diag reports two
sockets with the same inode number. It seems inet_csk_clone_lock copies
sk->sk_ino to child sockets, but sk_set_socket doesn’t reset it to zero
when sock is NULL.

[1] https://github.com/checkpoint-restore/criu/issues/2744

Thanks,
Andrei