Subject: Re: [PATCH] net: deadlock during net device unregistration - V2

From: Jarek Poplawski <[email-masked]>
Date: Thu, 2 Oct 2008 01:31:52 +0200

On Wed, Oct 01, 2008 at 11:06:22PM +0200, Daniel Lezcano wrote:
> Jarek Poplawski wrote:
>> On Wed, Oct 01, 2008 at 04:14:35PM +0200, Benjamin Thery wrote:
...
>>> --- net-next-2.6.orig/net/core/dst.c
>>> +++ net-next-2.6/net/core/dst.c
>>> @@ -328,6 +328,10 @@ static int dst_dev_event(struct notifier
>>>  			dst_ifdown(dst, dev, event != NETDEV_DOWN);
>>>  		}
>>>  		mutex_unlock(&dst_gc_mutex);
>>> +
>>> +		if (event == NETDEV_UNREGISTER &&
>>> +		    cancel_delayed_work(&dst_gc_work))
>>> +			dst_gc_task(&dst_gc_work.work);
>>
>> Hmm... It seems this shouldn't work yet: cancel_delayed_work() can only
>> kill this while on timer, but not when queued and maybe blocked already.

Hmm#2... Then maybe something like this?:

		if (event == NETDEV_UNREGISTER &&
	    	    (cancel_delayed_work(&dst_gc_work) ||
		     delayed_work_pending(&dst_gc_work)))
			dst_gc_task(&dst_gc_work.work);

Jarek P.