Re: xen kernel crash at boot since 23598:b24018319772

[Keir Fraser <keir.xen@gmail.com>]

On 01/07/2011 11:02, "Jan Beulich" <JBeulich@novell.com> wrote:

>>>> On 30.06.11 at 18:33, Keir Fraser <keir.xen@gmail.com> wrote:
>> Note that domain_spin_lock_irq_desc() has a retry loop for a reason! It
>> knows that pirq-irq mapping may change under its feet, so it needs to
>> re-check the mapping with the desc_lock held, at which point the mapping
>> cannot change *if* it obtained the correct desc_lock in time!
>> 
>> Perhaps pirq_spin_lock_irq_desc() needs a similar retry loop? Perhaps
> 
> Yes. Will send a patch soon.
> 
>> pirq_spin_lock_irq_desc() should never have been forked from
>> domain_spin_lock_irq_desc(), and all callers should simply use the former?
> 
> I'd rather not - the lookup isn't really inexpensive (and doesn't need
> to be re-done on each iteration either), which is why I created the
> clone in the first place. Instead I think that with adding the retry
> loop here, domain_spin_lock_irq_desc() could become a simple
> wrapper around pirq_spin_lock_irq_desc().

Yes please!

 -- Keir

> Jan
>