Re: [PATCH] x86: sysctl to allow panic on IOCK NMI error

Kurt Garloff
2009-07-03T09:19:18Z

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Ingo,

On Wed, Jul 01, 2009 at 01:10:03PM +0200, Ingo Molnar wrote:
> * Maciej W. Rozycki <macro@linux-mips.org> wrote:
>
> > On Tue, 30 Jun 2009, Greg KH wrote:
> >
> > > > These days an IOCK NMI typically happens in response to a PCI
> > > > SERR -- it may be useful to traverse PCI buses to find the
> > > > offender and dump this information on this occasion too. The
> > > > south bridge may have additional status too.
> > >
> > > Sure, that would be great to have. Care to make a patch? :)
> >
> > ENOTIME, sorry. Next year perhaps. Or a homework project for
> > one of the newbies. ;)
>
> You know that this project would kill a newbie, right? :)
>
> We have no real southbridge drivers on x86 - but we should certainly
> add some. Also, walking the PCI device tree from NMI context is
> tricky as the lists there are not NMI safe - we could crash if we
> happen to get a #IOCK while loading/unloading drivers (which is rare
> but could happen).

Well -- in case we panic the system anyway this is not necessarily a
big issue (let's print the message before ...) -- if we crash trying
to gather additional info, we'll lose the info. Currently we never have
the info ...

> IMHO it's all very much desired functionality, but highly
> non-trivial.

Too bad.

Best,
--
Kurt Garloff, VP OPS Partner Engineering -- Novell Inc.

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