Re: [tip:x86/irq] x86: apic: Fix mismerge, add arch_probe_nr_irqs() again

[Ingo Molnar <mingo@elte.hu>]

* Eric W. Biederman <ebiederm@xmission.com> wrote:

> Ingo Molnar <mingo@elte.hu> writes:
> 
> > * Yinghai Lu <yinghai@kernel.org> wrote:
> >
> >> 
> >> for x86, with radix tree based irq_to_desc(),
> >> removing arch_probe_nr_irqs is intentional. so we get more irq that could be used.
> >> 
> >> wonder if the udev for some of your test system have irq number limitation?
> >
> > was ancient udev: udev-095-17.fc6.
> 
> Something doesn't add up.  Nowhere in the udev source is there a
> single mention of irq.
> 
> gsi have fixed interrupt numbers so that would not change.
> 
> The dynamic irqs are allocated starting from the high gsi
> and working up.
> 
> The irq numbers that get allocated should not have changed,
> unless this was actually a bug fix in this configuration.
> 
> The other possibility is that somehow arch_probe_nr_irqs()
> was returning a number greater than NR_IRQS.
> 
> Ingo do you have any idea what NR_IRQS or nr_irqs were/are on
> that failing machine?

Sorry, not - and the merge window doesnt leave much time to revisit the 
problem right now.

But the failures were very real and 100% caused by this: they resulted in 
non-existent /dev/sda* nodes and resulting fsck failure by rc.

Thanks,

	Ingo