Kernel 3 Crashes on 4.2 unstable

Kernel 3 Crashes on 4.2 unstable

[Andi Reinbrech]

Hi,

I am unable to pinpoint this problem; on an old core2duo Xen 4.2 and 
kernel 3.0 as dom0 works, but on a newer i5 (same distro, same packages, 
all "baselined") the crashes as soon as Xen finishes booting.

The crash happens before anything useful is written to the serial 
console, and causes the machine a complete warm boot with no exceptions 
or error messages.

I have tried nomodeset, but I'm not sure the kernel gets as far as 
initialising graphics, it may still be in the stage of unpacking the initrd.

I would greatly appreciate any pointers to try an help to debug this, or 
hear from other testers with similar experience.

The config of kernel 3.0 I'm using is the "vanilla" fedora rawhide 
version, 3.0 however, not the latest git rc.


Thanks & kind regards,
Andi

Re: Kernel 3 Crashes on 4.2 unstable

[Pasi Kärkkäinen]

On Sun, Jul 31, 2011 at 09:07:02PM +0200, Andi Reinbrech wrote:
> Hi,
>
> I am unable to pinpoint this problem; on an old core2duo Xen 4.2 and  
> kernel 3.0 as dom0 works, but on a newer i5 (same distro, same packages,  
> all "baselined") the crashes as soon as Xen finishes booting.
>
> The crash happens before anything useful is written to the serial  
> console, and causes the machine a complete warm boot with no exceptions  
> or error messages.
>
> I have tried nomodeset, but I'm not sure the kernel gets as far as  
> initialising graphics, it may still be in the stage of unpacking the 
> initrd.
>
> I would greatly appreciate any pointers to try an help to debug this, or  
> hear from other testers with similar experience.
>
> The config of kernel 3.0 I'm using is the "vanilla" fedora rawhide  
> version, 3.0 however, not the latest git rc.
>

See http://wiki.xen.org/xenwiki/XenParavirtOps
the chapter called "Are there more debugging options I could enable to troubleshoot problems with Xen and/or dom0 kernel?"

Make sure you enable all those..

-- Pasi

Re: Kernel 3 Crashes on 4.2 unstable

[Andi Reinbrech]

On 2011/08/01 03:45 AM, Pasi Kärkkäinen wrote:
> On Sun, Jul 31, 2011 at 09:07:02PM +0200, Andi Reinbrech wrote:
>> Hi,
>>
>> I am unable to pinpoint this problem; on an old core2duo Xen 4.2 and
>> kernel 3.0 as dom0 works, but on a newer i5 (same distro, same packages,
>> all "baselined") the crashes as soon as Xen finishes booting.
>>
>> The crash happens before anything useful is written to the serial
>> console, and causes the machine a complete warm boot with no exceptions
>> or error messages.
>>
>> I have tried nomodeset, but I'm not sure the kernel gets as far as
>> initialising graphics, it may still be in the stage of unpacking the
>> initrd.
>>
>> I would greatly appreciate any pointers to try an help to debug this, or
>> hear from other testers with similar experience.
>>
>> The config of kernel 3.0 I'm using is the "vanilla" fedora rawhide
>> version, 3.0 however, not the latest git rc.
>>
> See http://wiki.xen.org/xenwiki/XenParavirtOps
> the chapter called "Are there more debugging options I could enable to troubleshoot problems with Xen and/or dom0 kernel?"
>
> Make sure you enable all those..
>
> -- Pasi
>
Thank you Pasi,

Will dig a bit deeper.  I saw that page also has very detailed 
instructions for a custom kernel, I will try and tune a little and 
compile a few versions.  I have a feeling it may very well be graphics 
related.  Will feed back here when I have details.

I have extensive C and hardware/embedded knowledge and would love to get 
a bit more involved in Xen.  Hopefully I can contribute, however small, 
here and there :-)

Kind regards,
Andi

Re: Kernel 3 Crashes on 4.2 unstable

[Konrad Rzeszutek Wilk]

On Mon, Aug 01, 2011 at 08:59:41PM +0200, Andi Reinbrech wrote:
> On 2011/08/01 03:45 AM, Pasi Kärkkäinen wrote:
> >On Sun, Jul 31, 2011 at 09:07:02PM +0200, Andi Reinbrech wrote:
> >>Hi,
> >>
> >>I am unable to pinpoint this problem; on an old core2duo Xen 4.2 and
> >>kernel 3.0 as dom0 works, but on a newer i5 (same distro, same packages,
> >>all "baselined") the crashes as soon as Xen finishes booting.

Does the kernel crash if you boot it as baremetal?

> >>
> >>The crash happens before anything useful is written to the serial
> >>console, and causes the machine a complete warm boot with no exceptions
> >>or error messages.
> >>
> >>I have tried nomodeset, but I'm not sure the kernel gets as far as
> >>initialising graphics, it may still be in the stage of unpacking the
> >>initrd.

<nods>
> >>
> >>I would greatly appreciate any pointers to try an help to debug this, or
> >>hear from other testers with similar experience.
> >>
> >>The config of kernel 3.0 I'm using is the "vanilla" fedora rawhide
> >>version, 3.0 however, not the latest git rc.
> >>
> >See http://wiki.xen.org/xenwiki/XenParavirtOps
> >the chapter called "Are there more debugging options I could enable to troubleshoot problems with Xen and/or dom0 kernel?"
> >
> >Make sure you enable all those..
> >
> >-- Pasi
> >
> Thank you Pasi,
> 
> Will dig a bit deeper.  I saw that page also has very detailed
> instructions for a custom kernel, I will try and tune a little and
> compile a few versions.  I have a feeling it may very well be
> graphics related.  Will feed back here when I have details.
> 
> I have extensive C and hardware/embedded knowledge and would love to
> get a bit more involved in Xen.  Hopefully I can contribute, however
> small, here and there :-)

Awesome. Not sure if the 'earlyprintk=xenboot' is mentioned in the Wiki but
that one is quite useful.

Re: Kernel 3 Crashes on 4.2 unstable

[Pasi Kärkkäinen]

On Tue, Aug 02, 2011 at 12:25:32PM -0400, Konrad Rzeszutek Wilk wrote:
> > 
> > Will dig a bit deeper.  I saw that page also has very detailed
> > instructions for a custom kernel, I will try and tune a little and
> > compile a few versions.  I have a feeling it may very well be
> > graphics related.  Will feed back here when I have details.
> > 
> > I have extensive C and hardware/embedded knowledge and would love to
> > get a bit more involved in Xen.  Hopefully I can contribute, however
> > small, here and there :-)
> 
> Awesome. Not sure if the 'earlyprintk=xenboot' is mentioned in the Wiki but
> that one is quite useful.

Hmm.. what's the difference between "earlyprintk=xen" and "earlyprintk=xenboot" ?

-- Pasi

Re: Kernel 3 Crashes on 4.2 unstable

[Konrad Rzeszutek Wilk]

On Tue, Aug 02, 2011 at 08:16:44PM +0300, Pasi Kärkkäinen wrote:
> On Tue, Aug 02, 2011 at 12:25:32PM -0400, Konrad Rzeszutek Wilk wrote:
> > > 
> > > Will dig a bit deeper.  I saw that page also has very detailed
> > > instructions for a custom kernel, I will try and tune a little and
> > > compile a few versions.  I have a feeling it may very well be
> > > graphics related.  Will feed back here when I have details.
> > > 
> > > I have extensive C and hardware/embedded knowledge and would love to
> > > get a bit more involved in Xen.  Hopefully I can contribute, however
> > > small, here and there :-)
> > 
> > Awesome. Not sure if the 'earlyprintk=xenboot' is mentioned in the Wiki but
> > that one is quite useful.
> 
> Hmm.. what's the difference between "earlyprintk=xen" and "earlyprintk=xenboot" ?

It has the same effect:

#ifdef CONFIG_HVC_XEN
		if (!strncmp(buf, "xen", 3))
			early_console_register(&xenboot_console, keep);
#endif

Just doing 'earlyprintk=xen' is enough. Not sure why I actually have 'xenboot' ..hmm

> 
> -- Pasi