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authorMatti Linnanvuori <mattilinnanvuori@yahoo.com>2008-02-13 02:10:11 -0500
committerDavid S. Miller <davem@davemloft.net>2008-02-13 02:11:16 -0500
commitd8b2a4d21e0b37b9669b202867bfef19f68f786a (patch)
tree4e60a1971f7705ea1837a3e5c1cb9b71c0bd7fa1
parentb318e0e4ef4e85812c25afa19f75addccc834cd4 (diff)
[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>
-rw-r--r--net/core/dev.c4
1 files changed, 2 insertions, 2 deletions
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)
1071 */ 1071 */
1072 call_netdevice_notifiers(NETDEV_GOING_DOWN, dev); 1072 call_netdevice_notifiers(NETDEV_GOING_DOWN, dev);
1073 1073
1074 dev_deactivate(dev);
1075
1076 clear_bit(__LINK_STATE_START, &dev->state); 1074 clear_bit(__LINK_STATE_START, &dev->state);
1077 1075
1078 /* Synchronize to scheduled poll. We cannot touch poll list, 1076 /* Synchronize to scheduled poll. We cannot touch poll list,
@@ -1083,6 +1081,8 @@ int dev_close(struct net_device *dev)
1083 */ 1081 */
1084 smp_mb__after_clear_bit(); /* Commit netif_running(). */ 1082 smp_mb__after_clear_bit(); /* Commit netif_running(). */
1085 1083
1084 dev_deactivate(dev);
1085
1086 /* 1086 /*
1087 * Call the device specific close. This cannot fail. 1087 * Call the device specific close. This cannot fail.
1088 * Only if device is UP 1088 * Only if device is UP