There is a race between sctp_rcv() and sctp_accept() where we
have moved the association from the listening socket to the
accepted socket, but sctp_rcv() processing cached the old
socket and continues to use it.
The easy solution is to check for the socket mismatch once we've
grabed the socket lock. If we hit a mis-match, that means
that were are currently holding the lock on the listening socket,
but the association is refrencing a newly accepted socket. We need
to drop the lock on the old socket and grab the lock on the new one.
A more proper solution might be to create accepted sockets when
the new association is established, similar to TCP. That would
eliminate the race for 1-to-1 style sockets, but it would still
existing for 1-to-many sockets where a user wished to peeloff an
association. For now, we'll live with this easy solution as
it addresses the problem.
Reported-by: Michal Hocko <mhocko@suse.cz>
Reported-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ae53b5bd77