Re: [Xen-devel] [PATCHv10 0/9] Xen: extend kexec hypercall for use with pv-ops kernels

[Don Slutz <dslutz@xxxxxxxxxxx>]

On 11/09/13 14:18, Daniel Kiper wrote:
> On Thu, Nov 07, 2013 at 10:16:51PM +0100, Daniel Kiper wrote:
> > On Wed, Nov 06, 2013 at 02:49:37PM +0000, David Vrabel wrote:
> > > The series (for Xen 4.4) improves the kexec hypercall by making Xen
> > > responsible for loading and relocating the image.  This allows kexec
> > > to be usable by pv-ops kernels and should allow kexec to be usable
> > > from a HVM or PVH privileged domain.
> > >
> > > I have now tested this with a Linux kernel image using the VGA console
> > > which was what was causing problems in v9 (this turned out to be a
> > > kexec-tools bug).
> > >
> > > The required patch series for kexec-tools will be posted shortly and
> > > are available from the xen-v7 branch of:
> > In general it works. However, quite often I am not able to execute panic
> > kernel. Machine hangs with following message:
> >
> > (XEN) Domain 0 crashed: Executing crash image
> >
> > gdb shows:
> >
> > (gdb) bt
> > #0  0xffff82d0801a0092 in do_nmi_crash (regs=<optimized out>) at crash.c:113
> > #1  0xffff82d0802281d9 in nmi_crash () at entry.S:666
> > #2  0x0000000000000000 in ?? ()
> > (gdb)
> >
> > Especially second bt line scares me... ;-)))
> >
> > I have not been able to identify why NMI was activated because
> > stack is completely cleared. I tried to record execution in gdb
> > but it stops with following message:
> >
> > cpumask_clear_cpu (dstp=0xffff82d0802f7f78 <call_data+24>, cpu=0)
> >      at /srv/dev/xen/xen_20130413_20131107.kexec/xen/include/xen/cpumask.h:108
> > 108             clear_bit(cpumask_check(cpu), dstp->bits);
> > Process record: failed to record execution log.
> >
> > Do you know how to find out why NMI was activated?
> >
> > I am able almost always reproduce this issue doing this:
> >    - boot Xen,
> >    - load panic kernel,
> >    - echo c > /proc/sysrq-trigger,
> >    - reboot from command line,
> >    - boot Xen,
> >    - load panic kernel,
> >    - echo c > /proc/sysrq-trigger.
> I am not able to reproduce this on real hardware. Sorry for confusion.
>
> Hence, for whole Xen kexec/kdump series:
>
> Reviewed-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
> Tested-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
>
> Daniel
Also

Tested-by: Don Slutz <dslutz@xxxxxxxxxxx>

   -Don Slutz
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