commit 430ff1d0b6e50d7665baf3d8dc1ef83d3295c9ad
Author: Matti Linnanvuori <[EMAIL PROTECTED]>
Date: Wed Mar 5 14:42:41 2008 -0800
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 <[EMAIL PROTECTED]>
Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
Signed-off-by: Chris Wright <[EMAIL PROTECTED]>
diff --git a/net/core/dev.c b/net/core/dev.c
index a347e75..4d44372 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
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