Subject: Re: net/unix: sk_socket can disappear when state is unlocked

From: Mark Salyzyn <[email-masked]>
Date: Fri, 22 May 2015 09:24:27 -0700

On 05/22/2015 08:35 AM, Hannes Frederic Sowa wrote:
> I still wonder if we need to actually recheck the condition and not
> simply break out of unix_stream_data_wait:
>
> We return to the unix_stream_recvmsg loop and recheck the
> sk_receive_queue. At this point sk_receive_queue is not really protected
> with unix_state_lock against concurrent modification with unix_release,
> as such we could end up concurrently dequeueing packets if socket is
> DEAD.
sock destroy(sic) is called before sock_orphan which sets SOCK_DEAD, so 
the receive queue has already been drained.

Sincerely -- Mark Salyzyn