Xen users - Jun 2007 - Xen 3.1 SEGV when running old binaries in FC1

I''ve just built Xen 3.1 x86 32 bit with PAE from source.

It runs most of my domUs just fine, windows etc, but it doesn''t run a
Fedora Core 1 image.  It hangs at 100% cpu usage just after it frees
kernel memory.

If I mount the FC1 image on dom0 and chroot into it I get

  # chroot . /bin/bash
  Segmentation fault

I can chroot into it using ash.static indicating it is something to do
with shared libraries.  I suspect something to do with the mapping of
linux-gate.so.1 which the FC1 binaries need.

I can run this domain just fine off Xen 3.0.4.

I suspect I''ve missed out a kernel option or something like that but I
can''t figure out what!

Any help most appreciated.

-- 
Nick Craig-Wood <nick@craig-wood.com> -- http://www.craig-wood.com/nick

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Hi Nick,

FC1 did have some crazy stuff going on (e.g. a 2.4 kernel with NPTL), so I 
guess it''s possible HVM mode isn''t handling that right for
some reason.

Is the Xen version the only thing you''ve changed between the two
installs?  If
so I guess it could be a regression that''ll need bugfixing.

Cheers,
Mark

On Thursday 07 June 2007, Nick Craig-Wood wrote:
> I''ve just built Xen 3.1 x86 32 bit with PAE from source.
>
> It runs most of my domUs just fine, windows etc, but it doesn''t
run a
> Fedora Core 1 image.  It hangs at 100% cpu usage just after it frees
> kernel memory.
>
> If I mount the FC1 image on dom0 and chroot into it I get
>
>   # chroot . /bin/bash
>   Segmentation fault
>
> I can chroot into it using ash.static indicating it is something to do
> with shared libraries.  I suspect something to do with the mapping of
> linux-gate.so.1 which the FC1 binaries need.
>
> I can run this domain just fine off Xen 3.0.4.
>
> I suspect I''ve missed out a kernel option or something like that
but I
> can''t figure out what!
>
> Any help most appreciated.


-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

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On Thu, Jun 07, 2007 at 07:05:21PM +0100, Mark Williamson
wrote:
> On Thursday 07 June 2007, Nick Craig-Wood wrote:
> > I''ve just built Xen 3.1 x86 32 bit with PAE from source.
> >
> > It runs most of my domUs just fine, windows etc, but it
doesn''t run a
> > Fedora Core 1 image.  It hangs at 100% cpu usage just after it frees
> > kernel memory.
> >
> > If I mount the FC1 image on dom0 and chroot into it I get
> >
> >   # chroot . /bin/bash
> >   Segmentation fault
> >
> > I can chroot into it using ash.static indicating it is something to do
> > with shared libraries.  I suspect something to do with the mapping of
> > linux-gate.so.1 which the FC1 binaries need.
> >
> > I can run this domain just fine off Xen 3.0.4.
>
> FC1 did have some crazy stuff going on (e.g. a 2.4 kernel with NPTL), so I 
> guess it''s possible HVM mode isn''t handling that right
for some reason.
It is a paravirt domain not HVM...
> Is the Xen version the only thing you''ve changed between the two
installs?  If
> so I guess it could be a regression that''ll need bugfixing.
I changed the xen hypervisor and the dom0 and domU kernels.  The I see
the same SEGV with the dom0 and domU kernels.

Everything else remained the same.

I''ve put a small ext2 filing system here which demonstrates the problem

  http://www.craig-wood.com/nick/pub/fedora_demo.gz

If mount it and attempt to chroot into it under Xen 3.1 then I get a
SEGV.  Chrooting into it from Xen 3.0.3 , Xen 3.0.4 and Debian testing
works fine.

-- 
Nick Craig-Wood <nick@craig-wood.com> -- http://www.craig-wood.com/nick

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What kernel are you running in the domU?

Cheers,
Mark

On Friday 08 June 2007, Nick Craig-Wood wrote:
> On Thu, Jun 07, 2007 at 07:05:21PM +0100, Mark Williamson wrote:
> > On Thursday 07 June 2007, Nick Craig-Wood wrote:
> > > I''ve just built Xen 3.1 x86 32 bit with PAE from source.
> > >
> > > It runs most of my domUs just fine, windows etc, but it
doesn''t run a
> > > Fedora Core 1 image.  It hangs at 100% cpu usage just after it
frees
> > > kernel memory.
> > >
> > > If I mount the FC1 image on dom0 and chroot into it I get
> > >
> > >   # chroot . /bin/bash
> > >   Segmentation fault
> > >
> > > I can chroot into it using ash.static indicating it is something
to do
> > > with shared libraries.  I suspect something to do with the
mapping of
> > > linux-gate.so.1 which the FC1 binaries need.
> > >
> > > I can run this domain just fine off Xen 3.0.4.
> >
> > FC1 did have some crazy stuff going on (e.g. a 2.4 kernel with NPTL),
so
> > I guess it''s possible HVM mode isn''t handling that
right for some reason.
>
> It is a paravirt domain not HVM...
>
> > Is the Xen version the only thing you''ve changed between the
two
> > installs?  If so I guess it could be a regression that''ll
need bugfixing.
>
> I changed the xen hypervisor and the dom0 and domU kernels.  The I see
> the same SEGV with the dom0 and domU kernels.
>
> Everything else remained the same.
>
> I''ve put a small ext2 filing system here which demonstrates the
problem
>
>   http://www.craig-wood.com/nick/pub/fedora_demo.gz
>
> If mount it and attempt to chroot into it under Xen 3.1 then I get a
> SEGV.  Chrooting into it from Xen 3.0.3 , Xen 3.0.4 and Debian testing
> works fine.


-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

On Fri, Jun 08, 2007 at 03:03:14PM +0100, Mark Williamson
wrote:
> What kernel are you running in the domU?
Both the dom0 and domU are running 2.6.18.8

I made these kernels by using "make mkpatches" and applying the patch
produced to a vanilla 2.6.18.8 as donwloaded from kernel.org.  There
was one reject which I ascertained was a patch that had already been
applied to the Xen kernel.

-- 
Nick Craig-Wood <nick@craig-wood.com> -- http://www.craig-wood.com/nick

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