Re: [PATCH] Fix NULL pointer for Xen guests

[Suresh Siddha <suresh.b.siddha@intel.com>]

On Wed, 2010-04-28 at 11:29 -0700, Prarit Bhargava wrote:
> 
> On 04/28/2010 02:26 PM, Andrew Morton wrote:
> > On Tue, 27 Apr 2010 11:24:42 -0400
> > Prarit Bhargava<prarit@redhat.com>  wrote:
> >
> >    
> >> Upstream PV guests fail to boot because of a NULL pointer.  It is possible that
> >> xen guests have irq_desc->chip_data = NULL.
> >>
> >> Test for NULL chip_data pointer before attempting to complete an irq move.
> >>
> >> Signed-off-by: Prarit Bhargava<prarit@redhat.com>
> >> Acked-by: Suresh Siddha<suresh.b.siddha@intel.com>
> >>
> >> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> >> index 127b871..eb2789c 100644
> >> --- a/arch/x86/kernel/apic/io_apic.c
> >> +++ b/arch/x86/kernel/apic/io_apic.c
> >> @@ -2545,6 +2545,9 @@ void irq_force_complete_move(int irq)
> >>   	struct irq_desc *desc = irq_to_desc(irq);
> >>   	struct irq_cfg *cfg = desc->chip_data;
> >>
> >> +	if (!cfg)
> >> +		return;
> >> +
> >>   	__irq_complete_move(&desc, cfg->vector);
> >>   }
> >>   #else
> >>      
> > I assume this is needed for 2.6.34?
> >
> > What about 2.6.33.x and earlier?
> >    
> 
> Hey Andrew,
> 
> I actually pinged Chris Wright to see about including this in the 
> -stable branches.  I haven't heard anything back so I'll reping him.

It will be applicable for 2.6.33 and beyond.

thanks,
suresh