Re: [PATCH net] af_unix: fix listen() succeeding on sockets in the wrong state

[Cong Wang]

On Thu, Jul 02, 2026 at 04:20:15PM -0400, John Ericson wrote:
> From: John Ericson <mail@xxxxxxxxxxxxxx>
> 
> Commit fd0a109a0f6b ("net, pidfs: prepare for handing out pidfds for
> reaped sk->sk_peer_pid") inserted a `prepare_peercred()` call between
> `err = -EINVAL` and the socket-state check in `unix_listen()`. Since
> `prepare_peercred()` leaves `err` at 0 on success, `listen()` on an
> AF_UNIX socket that is not in `TCP_CLOSE` or `TCP_LISTEN` state (e.g.
> one that is already connected) now silently returns success without
> doing anything, instead of failing with `EINVAL` as it did before.

Do you mind adding a selftest for this?

Thanks,
Cong