Re: Commit cb83b62 fails to boot with a divide by zero error.
From: Robin Holt
Date: Mon May 14 2012 - 08:40:33 EST
On Mon, May 14, 2012 at 12:48:29PM +0200, Ingo Molnar wrote:
> * Robin Holt <holt@xxxxxxx> wrote:
> > On Fri, May 11, 2012 at 05:36:13PM +0200, Peter Zijlstra wrote:
> > > On Fri, 2012-05-11 at 10:05 -0500, Robin Holt wrote:
> > > > On Fri, May 11, 2012 at 04:33:10PM +0200, Peter Zijlstra wrote:
> > > > > On Fri, 2012-05-11 at 08:39 -0500, Robin Holt wrote:
> > > > >
> > > > > > We found that reverting the commit:
> > > > > > cb83b62 (x86/sched/core) sched/numa: Rewrite the CONFIG_NUMA sched domain support
> > > > > >
> > > > > > also got things working.
> > > > >
> > > > > there's a particularly stupid bug in that code
> > > >
> > > > Even with that applied, I still get the divide by zero.
> > >
> > > Humm.. what kind of machine is this? And how far along does it get in
> > > booting? ->power isn't supposed to get to 0.
> > It is a four blade (8 socket 80 core 160 hyper-thread machine)
> > with 40 GB of RAM.
> > Looking at the earlier kernel messages, I am wondering if I
> > don't have a BIOS that is giving me crud. I have messages
> > about hyperthreads being on different nodes. That had not
> > been happening in the past. I don't have access to the
> > machine now, but the BIOS string that had printed out is from
> > a developer's debug version.
> > When I get access to the machine again (likely not until
> > Monday), I will flash a release BIOS and retest. Until then,
> > please feel free to ignore me.
> Please don't re-flash the BIOS! We want to fix this bug - the
> kernel should never crash on whatever topology data the BIOS
> We can sanitize it or ignore it, but crashing is not an option.
> So lets figure this out, ok?
I have the old BIOS as well so I can flash back. Plus, I have the
BIOS developer's description of his changes and he has saved his
workarea. Toggling back and forth should not be a problem to help
us determine the source and "correct" fix.
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