Re: BUG: null pointer deref in dmar_ir_support

From: Suresh Siddha
Date: Fri Apr 02 2010 - 14:29:54 EST

On Fri, 2010-04-02 at 11:20 -0700, Ingo Molnar wrote:
> * Suresh Siddha <suresh.b.siddha@xxxxxxxxx> wrote:
> > @@ -1640,8 +1640,10 @@ int __init APIC_init_uniprocessor(void)
> > }
> > #endif
> >
> > +#ifndef CONFIG_SMP
> > enable_IR_x2apic();
> > default_setup_apic_routing();
> > +#endif
> Instead of adding yet another ugly #ifdef please hide these details properly,
> by making enable_IR_x2apic() and default_setup_apic_routing() a NOP on !SMP.

Ingo, These are not nops on !SMP. We should call these functions from
APIC_init_uniprocessor() only if it is a UP kernel. For SMP kernel they
are called from some where else.

With the current code, on SMP and with non SMP motherboard we were
calling these routines twice which cause problem.

I wanted to keep the patch simple for urgent/backport. I will clean this
by restructuring the init code for 2.6.35


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