[RFC PATCH 0/4] USB: HCD/EHCI: giveback of URB in tasklet context

Ming Lei ming.lei at canonical.com
Wed Jun 12 06:11:34 EDT 2013


On Wed, Jun 12, 2013 at 5:11 PM, Oliver Neukum <oliver at neukum.org> wrote:
> On Tuesday 11 June 2013 15:10:03 Alan Stern wrote:
>> In order to prevent this from happening, you would have to change the
>> spin_lock() call in the completion handler to spin_lock_irqsave().
>> Furthermore, you will have to audit every USB driver to make sure that
>> all the completion handlers get fixed.
>
> Yes. However, it can be done mechanically. And we know only
> the handlers for complete need to be fixed.

I am wondering if the change is needed since timer function is still
run in softirq context instead of hard irq.

Looks Alan concerned that one USB interface driver may have another
hard interrupt handler involved. Is there such kind of USB driver/device
in tree?

Thanks,
--
Ming



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