• Andrea Righi's avatar
    xen-netfront: fix potential deadlock in xennet_remove() · c2c63310
    Andrea Righi authored
    There's a potential race in xennet_remove(); this is what the driver is
    doing upon unregistering a network device:
    
      1. state = read bus state
      2. if state is not "Closed":
      3.    request to set state to "Closing"
      4.    wait for state to be set to "Closing"
      5.    request to set state to "Closed"
      6.    wait for state to be set to "Closed"
    
    If the state changes to "Closed" immediately after step 1 we are stuck
    forever in step 4, because the state will never go back from "Closed" to
    "Closing".
    
    Make sure to check also for state == "Closed" in step 4 to prevent the
    deadlock.
    
    Also add a 5 sec timeout any time we wait for the bus state to change,
    to avoid getting stuck forever in wait_event().
    Signed-off-by: default avatarAndrea Righi <andrea.righi@canonical.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    c2c63310
xen-netfront.c 55.4 KB