tree 4e60a1971f7705ea1837a3e5c1cb9b71c0bd7fa1
parent b318e0e4ef4e85812c25afa19f75addccc834cd4
author Matti Linnanvuori <mattilinnanvuori@yahoo.com> 1202886611 -0800
committer David S. Miller <davem@davemloft.net> 1202886676 -0800

[NET]: Fix race in dev_close(). (Bug 9750)

There is a race in Linux kernel file net/core/dev.c, function dev_close.
The function calls function dev_deactivate, which calls function
dev_watchdog_down that deletes the watchdog timer. However, after that, a
driver can call netif_carrier_ok, which calls function
__netdev_watchdog_up that can add the watchdog timer again. Function
unregister_netdevice calls function dev_shutdown that traps the bug
!timer_pending(&dev->watchdog_timer). Moving dev_deactivate after
netif_running() has been cleared prevents function netif_carrier_on
from calling __netdev_watchdog_up and adding the watchdog timer again.

Signed-off-by: Matti Linnanvuori <mattilinnanvuori@yahoo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>