Re: [PATCH 1/3] x86: only call smp_processor_id in non-preempt cases
From: Ingo Molnar
Date: Thu Nov 18 2010 - 09:49:38 EST
* Don Zickus <dzickus@xxxxxxxxxx> wrote:
> On Thu, Nov 18, 2010 at 09:14:07AM +0100, Ingo Molnar wrote:
> >
> > * Don Zickus <dzickus@xxxxxxxxxx> wrote:
> >
> > > There are some paths that walk the die_chain with preemption on.
> >
> > What are those codepaths? At minimum it's worth documenting them.
>
> Well the one that caused the bug was do_general_protection which walks the
> die_chain with DIE_GPF.
>
> I can document them, though it might be time consuming to audit them and hope they
> don't change.
Listing one example is enough.
> [...] I guess my bigger question is, is it expected that anyone who calls the
> die_chain to have preemption disabled? If not, then does it matter if we document
> it?
Yes, it might be a bug to call those handlers with preemption on (or even with irqs
on). But if the code is fine as-is then documenting a single example would be nice.
Thanks,
Ingo
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