Peter Zijlstra wrote:
> On Fri, 2008-02-15 at 11:46 -0500, Gregory Haskins wrote:
>   
>
>> but perhaps you can convince me that it is not needed? 
>> (i.e. I am still not understanding how the timer guarantees the stability).
>>     
>
> ok, let me try again.
>
> So we take rq->lock, at this point we know rd is valid.
> We also know the timer is active.
>
> So when we release it, the last reference can be dropped and we end up
> in the hrtimer_cancel(), right before the kfree().
>
> hrtimer_cancel() will wait for the timer to end. therefore delaying the
> kfree() until the running timer finished.
>
>   

Ok, I see it now.  I agree that I think it is safe.  Thanks!

-Greg