Re: [PATCH 1/4] module: implement module_inhibit_unload()

From: Tejun Heo
Date: Tue Sep 25 2007 - 10:32:10 EST


Alan Stern wrote:
>> The unloading can proceed once module_unload_inhibit_cnt reaches zero.
>> An unloading thread only has to care about inhibition put in effect
>> before unloading has started, so there's no need to check again.
>
> You haven't fully answered Jon's question. Suppose
> module_unload_inhibit_cnt is nonzero, so the task adds itself to the
> module_unload_wait queue, changes to TASK_UNINTERRUPTIBLE, and calls
> schedule. There's nothing to prevent somebody else from waking the
> task back up before the original inhibition has been lifted.

Hmmm... I might be missing something here. Who else can wake up a
thread in uninterruptible sleep?

Thanks.

--
tejun
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