From: Matti Linnanvuori Date: Wed, 5 Mar 2008 22:42:41 +0000 (-0800) Subject: NET: Fix race in dev_close(). (Bug 9750) X-Git-Tag: v2.6.24.4~70 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=430ff1d0b6e50d7665baf3d8dc1ef83d3295c9ad;p=thirdparty%2Fkernel%2Fstable.git NET: Fix race in dev_close(). (Bug 9750) Upstream commit: d8b2a4d21e0b37b9669b202867bfef19f68f786a 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 Signed-off-by: Greg Kroah-Hartman Signed-off-by: Chris Wright --- diff --git a/net/core/dev.c b/net/core/dev.c index a347e75dcc1fc..4d44372db5f72 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1068,8 +1068,6 @@ 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, @@ -1080,6 +1078,8 @@ 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