* [Bug 9750] [patch 2.6.25] dev: avoid a race that triggers assertion failure
@ 2008-02-12 10:45 Matti Linnanvuori
2008-02-12 15:58 ` Jeff Garzik
2008-02-13 2:16 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Matti Linnanvuori @ 2008-02-12 10:45 UTC (permalink / raw)
To: jgarzik, netdev; +Cc: bugme-daemon
From: Matti Linnanvuori <mattilinnanvuori@yahoo•com>
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>
---
--- linux-2.6.25/net/core/dev.c 2008-02-12 12:37:51.206833000 +0200
+++ b/net/core/dev.c 2008-02-12 12:38:48.727611400 +0200
@@ -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 +1081,7 @@ 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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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [Bug 9750] [patch 2.6.25] dev: avoid a race that triggers assertion failure
2008-02-12 10:45 [Bug 9750] [patch 2.6.25] dev: avoid a race that triggers assertion failure Matti Linnanvuori
@ 2008-02-12 15:58 ` Jeff Garzik
2008-02-13 2:16 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Jeff Garzik @ 2008-02-12 15:58 UTC (permalink / raw)
To: Matti Linnanvuori; +Cc: netdev, David Miller
Matti Linnanvuori wrote:
> From: Matti Linnanvuori <mattilinnanvuori@yahoo•com>
>
> 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>
>
> ---
>
> --- linux-2.6.25/net/core/dev.c 2008-02-12 12:37:51.206833000 +0200
> +++ b/net/core/dev.c 2008-02-12 12:38:48.727611400 +0200
> @@ -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 +1081,7 @@ 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
This is more for davem (he does net/* stuff)
Jeff
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Bug 9750] [patch 2.6.25] dev: avoid a race that triggers assertion failure
2008-02-12 10:45 [Bug 9750] [patch 2.6.25] dev: avoid a race that triggers assertion failure Matti Linnanvuori
2008-02-12 15:58 ` Jeff Garzik
@ 2008-02-13 2:16 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2008-02-13 2:16 UTC (permalink / raw)
To: mattilinnanvuori; +Cc: jgarzik, netdev, bugme-daemon
From: Matti Linnanvuori <mattilinnanvuori@yahoo•com>
Date: Tue, 12 Feb 2008 02:45:22 -0800 (PST)
> From: Matti Linnanvuori <mattilinnanvuori@yahoo•com>
>
> 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>
Your patch won't apply because it has been whitespace damanged
by your email client.
This is what I let you know last time you posted this patch.
Please fix this up so that your patch can be applied.
Thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2008-02-12 10:45 [Bug 9750] [patch 2.6.25] dev: avoid a race that triggers assertion failure Matti Linnanvuori
2008-02-12 15:58 ` Jeff Garzik
2008-02-13 2:16 ` David Miller
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