crash cannot work for the newest qemu's core
 

Hi, all

When I use crash to deal with the vmcore generated by 'vrish dump', I meet the following
error:

crash: seek error: kernel virtual address: ffffffff8180f1e0 type: "cpu_possible_mask".

When I specify '-d 8' to get more information, I found the following message:

NOTE: KVM/QEMU CPU_SAVE_VERSION 12 is greater than supported version 9

So I guess crash does not support it now. Does anyone have plan to fix it?

Thanks
Wen Congyang

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crash cannot work for the newest qemu's core
 

----- Original Message -----
> Hi, all
>
> When I use crash to deal with the vmcore generated by 'vrish dump', I
> meet the following error:
>
> crash: seek error: kernel virtual address: ffffffff8180f1e0 type: "cpu_possible_mask".
>
> When I specify '-d 8' to get more information, I found the following message:
>
> NOTE: KVM/QEMU CPU_SAVE_VERSION 12 is greater than supported version 9
>
> So I guess crash does not support it now. Does anyone have plan to fix it?
>
> Thanks
> Wen Congyang

Hi Wen,

Also, because of your familiarity with this area, I certainly invite you
to take a look at this... ;-)

Thanks,
Dave


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crash cannot work for the newest qemu's core
 

----- Original Message -----
>
>
> ----- Original Message -----
> > Hi, all
> >
> > When I use crash to deal with the vmcore generated by 'vrish dump',
> > I
> > meet the following error:
> >
> > crash: seek error: kernel virtual address: ffffffff8180f1e0 type: "cpu_possible_mask".
> >
> > When I specify '-d 8' to get more information, I found the following message:
> >
> > NOTE: KVM/QEMU CPU_SAVE_VERSION 12 is greater than supported version 9
> >
> > So I guess crash does not support it now. Does anyone have plan to fix it?
> >
> > Thanks
> > Wen Congyang
>
> Hi Wen,
>
> Also, because of your familiarity with this area, I certainly invite you
> to take a look at this... ;-)
>
> Thanks,
> Dave

Hi Wen,

On a related note, what is the status with your "virsh dump-guest-memory"
replacement of "virsh dump"? The last I saw, it seemed like the qemu guys
finally seemed willing to accept it?

Dave

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crash cannot work for the newest qemu's core
 

At 06/22/2012 02:03 AM, Dave Anderson Wrote:
>
>
> ----- Original Message -----
>> Hi, all
>>
>> When I use crash to deal with the vmcore generated by 'vrish dump', I
>> meet the following error:
>>
>> crash: seek error: kernel virtual address: ffffffff8180f1e0 type: "cpu_possible_mask".
>>
>> When I specify '-d 8' to get more information, I found the following message:
>>
>> NOTE: KVM/QEMU CPU_SAVE_VERSION 12 is greater than supported version 9
>>
>> So I guess crash does not support it now. Does anyone have plan to fix it?
>>
>> Thanks
>> Wen Congyang
>
> Hi Wen,
>
> Also, because of your familiarity with this area, I certainly invite you
> to take a look at this... ;-)

I am busy recently. If I have time and the problem is not fixed, I will try to
fix it.

Thanks
Wen Congyang

>
> Thanks,
> Dave
>
>

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crash cannot work for the newest qemu's core
 

At 06/22/2012 09:06 PM, Dave Anderson Wrote:
>
>
> ----- Original Message -----
>>
>>
>> ----- Original Message -----
>>> Hi, all
>>>
>>> When I use crash to deal with the vmcore generated by 'vrish dump',
>>> I
>>> meet the following error:
>>>
>>> crash: seek error: kernel virtual address: ffffffff8180f1e0 type: "cpu_possible_mask".
>>>
>>> When I specify '-d 8' to get more information, I found the following message:
>>>
>>> NOTE: KVM/QEMU CPU_SAVE_VERSION 12 is greater than supported version 9
>>>
>>> So I guess crash does not support it now. Does anyone have plan to fix it?
>>>
>>> Thanks
>>> Wen Congyang
>>
>> Hi Wen,
>>
>> Also, because of your familiarity with this area, I certainly invite you
>> to take a look at this... ;-)
>>
>> Thanks,
>> Dave
>
> Hi Wen,
>
> On a related note, what is the status with your "virsh dump-guest-memory"
> replacement of "virsh dump"? The last I saw, it seemed like the qemu guys
> finally seemed willing to accept it?

dump-guest-memory is not a virsh's sub command. It is a qemu monitor command.
The patches for qemu and libvirt have been merged into newest qemu/libvirt.

Thanks
Wen Congyang

>
> Dave
>
>

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crash cannot work for the newest qemu's core
 

----- Original Message -----
> At 06/22/2012 09:06 PM, Dave Anderson Wrote:
> >
> >
> > ----- Original Message -----
> >>
> >>
> >> ----- Original Message -----
> >>> Hi, all
> >>>
> >>> When I use crash to deal with the vmcore generated by 'vrish dump',
> >>> I meet the following error:
> >>>
> >>> crash: seek error: kernel virtual address: ffffffff8180f1e0 type: "cpu_possible_mask".
> >>>
> >>> When I specify '-d 8' to get more information, I found the following message:
> >>>
> >>> NOTE: KVM/QEMU CPU_SAVE_VERSION 12 is greater than supported version 9
> >>>
> >>> So I guess crash does not support it now. Does anyone have plan to fix it?
> >>>
> >>> Thanks
> >>> Wen Congyang
> >>
> >> Hi Wen,
> >>
> >> Also, because of your familiarity with this area, I certainly invite you
> >> to take a look at this... ;-)
> >>
> >> Thanks,
> >> Dave
> >
> > Hi Wen,
> >
> > On a related note, what is the status with your "virsh dump-guest-memory"
> > replacement of "virsh dump"? The last I saw, it seemed like the qemu guys
> > finally seemed willing to accept it?
>
> dump-guest-memory is not a virsh's sub command. It is a qemu monitor command.
> The patches for qemu and libvirt have been merged into newest qemu/libvirt.

OK, but now I'm confused...

I was presuming that you could run the new "dump-guest-memory" command from
the KVM host, specifying a particular guest, and it will create an ELF vmcore
that the crash utility can read. But I don't know what the term "qemu monitor
command" means? Is it a command that can be executed from a shell command line?

And will "virsh dump" still exist? And if so, why?

Dave

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crash cannot work for the newest qemu's core
 

----- Original Message -----
> At 06/22/2012 02:03 AM, Dave Anderson Wrote:
> >
> >
> > ----- Original Message -----
> >> Hi, all
> >>
> >> When I use crash to deal with the vmcore generated by 'vrish dump', I
> >> meet the following error:
> >>
> >> crash: seek error: kernel virtual address: ffffffff8180f1e0 type: "cpu_possible_mask".
> >>
> >> When I specify '-d 8' to get more information, I found the following message:
> >>
> >> NOTE: KVM/QEMU CPU_SAVE_VERSION 12 is greater than supported version 9
> >>
> >> So I guess crash does not support it now. Does anyone have plan to fix it?
> >>
> >> Thanks
> >> Wen Congyang
> >
> > Hi Wen,
> >
> > Also, because of your familiarity with this area, I certainly invite you
> > to take a look at this... ;-)
>
> I am busy recently. If I have time and the problem is not fixed, I will try to
> fix it.

OK thanks, I appreciate that.

Dave

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crash cannot work for the newest qemu's core
 

From: Dave Anderson <anderson@redhat.com>
Subject: Re: [Crash-utility] crash cannot work for the newest qemu's core
Date: Thu, 28 Jun 2012 16:38:56 -0400

>
>
> ----- Original Message -----
>> At 06/22/2012 09:06 PM, Dave Anderson Wrote:
>> >
>> >
>> > ----- Original Message -----
>> >>
>> >>
>> >> ----- Original Message -----
>> >>> Hi, all
>> >>>
>> >>> When I use crash to deal with the vmcore generated by 'vrish dump',
>> >>> I meet the following error:
>> >>>
>> >>> crash: seek error: kernel virtual address: ffffffff8180f1e0 type: "cpu_possible_mask".
>> >>>
>> >>> When I specify '-d 8' to get more information, I found the following message:
>> >>>
>> >>> NOTE: KVM/QEMU CPU_SAVE_VERSION 12 is greater than supported version 9
>> >>>
>> >>> So I guess crash does not support it now. Does anyone have plan to fix it?
>> >>>
>> >>> Thanks
>> >>> Wen Congyang
>> >>
>> >> Hi Wen,
>> >>
>> >> Also, because of your familiarity with this area, I certainly invite you
>> >> to take a look at this... ;-)
>> >>
>> >> Thanks,
>> >> Dave
>> >
>> > Hi Wen,
>> >
>> > On a related note, what is the status with your "virsh dump-guest-memory"
>> > replacement of "virsh dump"? The last I saw, it seemed like the qemu guys
>> > finally seemed willing to accept it?
>>
>> dump-guest-memory is not a virsh's sub command. It is a qemu monitor command.
>> The patches for qemu and libvirt have been merged into newest qemu/libvirt.
>
> OK, but now I'm confused...
>
> I was presuming that you could run the new "dump-guest-memory" command from
> the KVM host, specifying a particular guest, and it will create an ELF vmcore
> that the crash utility can read. But I don't know what the term "qemu monitor
> command" means? Is it a command that can be executed from a shell command line?
>
> And will "virsh dump" still exist? And if so, why?
>
> Dave

This is a patch set in libvirt side:

https://www.redhat.com/archives/libvir-list/2012-June/msg00404.html

In summary:

- dump-guest-memory is a qemu monitor command, the protocol of which
is explained in http://wiki.qemu.org/QMP.

- To get ELF-formatted vmcore, we specify --memory-only option to
virsh dump command, then virsh dump uses dump-guest-memory monitor
command vir QMP protocol, instead of migrate monitor command.

- Note that the default behaviour remains calling migrate command.


BTW, we can call monitor commands using virsh qemu-monitor-command but
they are restricted, according to this FAQ:

- http://wiki.libvirt.org/page/FAQ#Can_I_connect_to_the_QEMU_monitor_with_libvirt .3F

Also, this is helpful to know how virsh commands use qemu monitor
commands:

- http://wiki.libvirt.org/page/QEMUSwitchToLibvirt#Monitor_command_equivalence


Thanks.
HATAYAMA, Daisuke

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