Re: Re: [Xen-users] Hypervisor hangs on startup, 2.6.32-5-xen dom0 kernel panic

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Wed, Jan 05, 2011 at 05:05:50PM +0100, Arno Toell wrote:
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> > This suggests that the xen_exchange_memory hypercall has failed for some
> > reason.
> > 
> > -12 is -ENOMEM but size is only 64M and this is start of day so I can't
> > think why this would be the case (or at least why it wouldn't always be
> > the case if it was happening at all).
> 
> I was speaking earlier today to Pasi about this bug again by accident.
> There he asked whether I did try to boot the xen-4.0-testing tree. Now I
> did, as I built the most recent -testing snapshot and I have some more
> to add:
> 
> Booting the Xen hypervisor in version 4.0.2-rc1-pre built by myself on
> the affected system resulted in no failure for Debian's stock
> 2.6.32-5-xen-amd64 kernel. Jeremy's xen tree at
> git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git (resulting
> in 2.6.32.27) failed to boot, but that is my fault as I was too lazy to
> build an appropriate .config. So this is NOT related to the bug.
> 
> So the question is now, whether there was a bug in 4.0.1 that has been
> fixed in -testing which fixes this one as well (or if it is a duplicate

There was some fix for the VT-d allocation that ended up crashing Dom0
(b/c of an memory accounting issue).

It could have been that was what you hit. I don't remember the changeset
number, but you could try booting your old hypervisor without the Vt-D
and see if that was it (iommu=off) ?