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Re: [Xen-devel] xen.git branch reorg / crash with 2.6.30-rc3 pv_ops dom0

On Wed, Apr 29, 2009 at 09:25:24AM -0700, Jeremy Fitzhardinge wrote:
> > There was some unification work in this area around the
> >beginning of March although I'm pretty such I've had it work much more
> >recently. (I guess it might not have been merged into a visible branch
> >until more recently, it's a bit hard to tell with git but I don't think
> >that's what happened).
> Yeah, I think it has been working properly for some since then, though I 
> think Pasi has been reporting problems since 32-bit dom0 first booted.

Yep, I've had problems from the beginning.. 

dom0/hackery was working pretty OK for me before it was removed.. 
I could run and install new PV guests etc.

> My symptoms are a bit all over the place.  For a while I was just seeing 
> writes-to-RO pages, but since I added some debugging to try and work out 
> where that was happening, I'm now seeing more major pagetable corruption 
> (like instruction fetches failing because of reserved bits being set in 
> the pagetable...).  So something is stomping pagetable, and I think its 
> some page being freed.
> I think these are somewhat similar to Pasi's symptoms which he said that 
> disabling HIGHPTE fixed.   I see problems independent of the HIGHPTE 
> setting.

CONFIG_HIGHPTE=n fixed my "dom0 kernel crashes while compiling kernel source in 
dom0" test.. 
could be the problem still happens with some other tests though.. 

> I have best success in causing crashes when scp'ing a 8GB file onto my 
> XFS /home filesystem.  XFS does quite a lot of vmapping, so that may 
> exacerbate the problem.

I could try scp aswell.. 

> I also realized that my Xen doesn't have debug=y set, so I'm probably 
> missing some information.

Hmm, good point. I don't have debug=y either.. 

-- Pasi

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