• Sowmini Varadhan's avatar
    rds: cancel send/recv work before queuing connection shutdown · aed20a53
    Sowmini Varadhan authored
    We could end up executing rds_conn_shutdown before the rds_recv_worker
    thread, then rds_conn_shutdown -> rds_tcp_conn_shutdown can do a
    sock_release and set sock->sk to null, which may interleave in bad
    ways with rds_recv_worker, e.g., it could result in:
    
    "BUG: unable to handle kernel NULL pointer dereference at 0000000000000078"
        [ffff881769f6fd70] release_sock at ffffffff815f337b
        [ffff881769f6fd90] rds_tcp_recv at ffffffffa043c888 [rds_tcp]
        [ffff881769f6fdb0] rds_recv_worker at ffffffffa04a4810 [rds]
        [ffff881769f6fde0] process_one_work at ffffffff810a14c1
        [ffff881769f6fe40] worker_thread at ffffffff810a1940
        [ffff881769f6fec0] kthread at ffffffff810a6b1e
    
    Also, do not enqueue any new shutdown workq items when the connection is
    shutting down (this may happen for rds-tcp in softirq mode, if a FIN
    or CLOSE is received while the modules is in the middle of an unload)
    Signed-off-by: default avatarSowmini Varadhan <sowmini.varadhan@oracle.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    aed20a53
connection.c 19.7 KB