From d8b2a4d21e0b37b9669b202867bfef19f68f786a Mon Sep 17 00:00:00 2001 From: Matti Linnanvuori Date: Tue, 12 Feb 2008 23:10:11 -0800 Subject: [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 Signed-off-by: David S. Miller --- net/core/dev.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 9549417250bb..6cfc1238c4a6 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1071,8 +1071,6 @@ int dev_close(struct net_device *dev) */ call_netdevice_notifiers(NETDEV_GOING_DOWN, dev); - dev_deactivate(dev); - clear_bit(__LINK_STATE_START, &dev->state); /* Synchronize to scheduled poll. We cannot touch poll list, @@ -1083,6 +1081,8 @@ int dev_close(struct net_device *dev) */ smp_mb__after_clear_bit(); /* Commit netif_running(). */ + dev_deactivate(dev); + /* * Call the device specific close. This cannot fail. * Only if device is UP -- cgit v1.2.3-59-g8ed1b