Re: [PATCH] Bluetooth: HIDP: guard session->conn in hidp_connection_del

[Pauli Virtanen]

Hi,

ke, 2026-04-22 kello 11:09 -0400, Michael Bommarito kirjoitti:
> On Wed, Apr 22, 2026 at 10:55 AM Luiz Augusto von Dentz
> <luiz.dentz@xxxxxxxxx> wrote:
> > We might need a lock in order to access the session->conn:
> 
> This one is a little easier than the other txwin_size issue in terms
> of blast radius.
> 
> What pattern would you prefer here?
> 
> Option 1, smaller but ordering questions: hold the semaphore across
> check and use like this:
> 
> down_read(&hidp_session_sem);
> if (session->conn)
>     l2cap_unregister_user(session->conn, &session->user);
> up_read(&hidp_session_sem)
> 
> 
> Option 2, more correct but more cycles: snapshot the conn and use outside
> 
> down_read(&hidp_session_sem);
> conn = session->conn;
> if (conn)
>     l2cap_conn_get(conn);
> up_read(&hidp_session_sem);
> if (conn) {
>     l2cap_unregister_user(conn, &session->user);
>     l2cap_conn_put(conn);
> }

I'm not sure now (would need to rethink it through), but one probably
should check if dbf666e4fc9b is needed or whether 752a6c9596d alone
would be enough to address the original issue.

-- 
Pauli Virtanen