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

[Don Slutz]

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 at oracle.com>
> Tested-by: Daniel Kiper <daniel.kiper at oracle.com>
>
> Daniel
Also

Tested-by: Don Slutz <dslutz at verizon.com>

    -Don Slutz
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