preempt crash in 2.6.18

[Benjamin Herrenschmidt]

On Sat, 2006-10-14 at 01:21 +0400, Vitaly Bordug wrote:
> On Fri, 13 Oct 2006 09:16:52 -0500
> Rune Torgersen wrote:
> 
> > 
> > This is from a Freescale 8265 running 2.6.18
> > Anyone have any idea what this is and how to fix it?
> > 
> Yes. Actually, I recall alike thing and used to fix with proper spin-locking if the 
> cascade PCI irq, which apparently does do_irq that seems to confuse preempt counters.
> 
> Just a pure guess.

How so ? Cascades shouldn't do do_IRQ with the new irq code anyway
unless this is still arch/ppc, they should do either __do_IRQ or better,
generic_handle_irq().

Ben.