There is a race on sk_receive_queue between llc_ui_recvmsg and
sock_queue_rcv_skb.

Our current solution is to protect skb_eat in llc_ui_recvmsg
with the queue spinlock.
Signed-off-by: NRadu Iliescu <riliescu@ixiacom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>