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Date: Tue, 6 Mar 2007 03:09:27 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: 2.6.21-rc2-mm2
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	<20070306192718.999e114d.kamezawa.hiroyu@jp.fujitsu.com>
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On Tue, 6 Mar 2007 19:27:18 +0900 KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> 
> Following panic ouccurred (always) on ia64/NUMA(with empty node.)
> 
> Bug in here.
> ==
> void move_native_irq(int irq)
> {
>         struct irq_desc *desc = irq_desc + irq;
> 
>         if (likely(!(desc->status & IRQ_MOVE_PENDING)))
>                 return;
> 
>         if (unlikely(desc->status & IRQ_DISABLED))
>                 return;
> 
>         desc->chip->mask(irq);  <---------maybe this *mask* is NULL pointer
>         move_masked_irq(irq);
>         desc->chip->unmask(irq);
> }
> ==
> 
> Is "mask"  always valid pointer ?

I can only find two `struct irq_chip's in arch/ia64 and they both have a
.mask.  And a .unmask.  So perhaps that is a misreading of what oopsed.

There are no changes in kernel/irq/ in -mm.  Are you sure mainline doesn't
do this too?

Anyway, can you please take a closer look at exactly what pointer it is
oopsing on?