[Jaunty SRU] LP#345710 [v2: description modified] iwl3945: cancel rfkill_poll with sync when?the module is exiting

Huaxu Wan huaxu.wan at linux.intel.com
Thu Jun 11 02:42:25 UTC 2009


Hi Stefan,

The patch 71d449b55abf5018d7c711b2b62abc0c083723c4 doesn't work in my test
with 2.6.28 kernel. Please double check before it's pulled in.

Thanks
Huaxu

On 15:53 Wed 10 Jun, Stefan Bader wrote:
> Hi Huaxu,
>
> thanks for the work and sorry for being so late in response. It seems, by 
> now the patch made it upstream as
>
> commit 71d449b55abf5018d7c711b2b62abc0c083723c4
> Author: Reinette Chatre <reinette.chatre at intel.com>
> Date:   Mon Apr 20 14:37:01 2009 -0700
>
>     iwl3945: use cancel_delayed_work_sync to cancel rfkill_poll
>
>     Users reported lockup with work still trying to run
>     after module has been unloaded.
>
>     http://thread.gmane.org/gmane.linux.kernel.wireless.general/30594/focus=3060
>
>     Signed-off-by: Reinette Chatre <reinette.chatre at intel.com>
>     Reported-by: TJ <ubuntu at tjworld.net>
>     Reported-by: Huaxu Wan <huaxu.wan at linux.intel.com>
>     Signed-off-by: John W. Linville <linville at tuxdriver.com>
>
>
> This looks even simpler by just syncing the cancellation. I will go on 
> and try to get this version into SRU. Thanks again.
>
> Stefan
>
> Huaxu Wan wrote:
>> From f3628f0ac6c9713afadaa9654815c37a294ce7e2 Mon Sep 17 00:00:00 2001
>> From: Huaxu Wan <huaxu.wan at linux.intel.com>
>> Date: Fri, 8 May 2009 07:36:58 -0400
>> Subject: [PATCH] cancel rfkill_poll with sync when module is exiting
>>
>> Re-write the patch due to there is no response from TJ.
>>
>> When the the interface is down, a delayed work rfkill_poll is queued.
>> This work must be canceled before the module is unloaded, or the OS would
>> suffer a hard lock-up.
>>  This patch fix the bug LP: #345710 by make sure the queued work is 
>> canceled.
>>
>>
>> Original info:
>> http://marc.info/?l=linux-wireless&m=123791044313158&w=2
>> Bug: #345710
>>
>> When the wireless interface is active and the iwl3945 module is unloaded the
>> call to ieee80211_unregister_hw() would call iwl3945_mac_stop() which would
>> restart the delayed workqueue for rfkill_poll. That workqueue had already been
>> cancelled so when the next work item was run (2 seconds later) the system would
>> suffer a hard lock-up because the module had been unloaded by then.
>>
>> This patch implements STATUS_EXIT_PENDING checks in places where the rfkill_poll
>> work is scheduled, and moves the final workqueue cancellation to occur after the
>> call to ieee80211_unregister_hw().
>>
>> Bug discovered, experienced and fix tested on my PC.
>>
>> Signed-off-by: TJ <ubuntu at tjworld.net>
>> Signed-off-by: Huaxu Wan <huaxu.wan at linux.intel.com>
>> ---
>>  drivers/net/wireless/iwlwifi/iwl3945-base.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
>> index bb92db2..08c2a9d 100644
>> --- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
>> +++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
>> @@ -8166,7 +8166,6 @@ static void __devexit iwl3945_pci_remove(struct pci_dev *pdev)
>>  	sysfs_remove_group(&pdev->dev.kobj, &iwl3945_attribute_group);
>>   	iwl3945_rfkill_unregister(priv);
>> -	cancel_delayed_work(&priv->rfkill_poll);
>>  	iwl3945_dealloc_ucode_pci(priv);
>>   	if (priv->rxq.bd)
>> @@ -8181,6 +8180,7 @@ static void __devexit iwl3945_pci_remove(struct pci_dev *pdev)
>>   	/*netif_stop_queue(dev); */
>>  	flush_workqueue(priv->workqueue);
>> +	cancel_delayed_work_sync(&priv->rfkill_poll);
>>   	/* ieee80211_unregister_hw calls iwl3945_mac_stop, which flushes
>>  	 * priv->workqueue... so we can't take down the workqueue
>
>
> -- 
>
> When all other means of communication fail, try words!
>
>

-- 
Thanks
Huaxu




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