Re: linux-next: User Mode Linux broken

From: Thomas Gleixner
Date: Fri Oct 22 2010 - 03:04:11 EST


On Thu, 21 Oct 2010, Richard Weinberger wrote:
> Am Donnerstag 21 Oktober 2010, 21:45:35 schrieb Thomas Gleixner:
> > Why shold it solve it ? irq_enable is set to compat_irq_enable which
> > in turn calls chip->enable.
> >
> > So how's that different ?
>
> I took a closer look on the issue.
>
> check_irq_resend() gets called before irq_chip_set_defaults().
> In the first call to check_irq_resend() desc->irq_data.chip->irq_enable is
> NULL. UML dies due to a NULL-pointer dereference...
>
> I don't know why check_irq_resend() is called before irq_chip_set_defaults().
> It's your code. ;-)

Well, but it only gets called via enable_irq(). So that means
something is calling enable_irq _before_ request/setup_irq().

arch/um/kernel/irq.c:init_IRQ() does that :)

Thanks,

tglx
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