Re: [PATCH 1/4] stack overflow safe kdump (i386) - safe_smp_processor_id

[Andi Kleen]

Fernando Luis Vazquez Cao <fernando@xxxxxxxxxxxxxxxxx> writes:
> 
> To circumvent this problem I suggest implementing
> "safe_smp_processor_id()" (it already exists on x86_64) for i386 and
> IA64 and use it as a replacement to smp_processor_id in the reboot path
> to the dump capture kernel. This is a possible implementation for i386.

It's not fully safe, because a SMP kernel might run on a 32bit
system without APIC. Then hard_smp_processor_id() would fault. 
(this cannot happen on x86-64)

You probably need to check one of the globals set by apic.c
when its disabled.

-Andi
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