Re: [Xen-devel] Re: Xen-4.0.x doesn't start on 32bit / pvops 2.6.32.19

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Mon, Aug 16, 2010 at 12:54:05PM +0200, Stefan Kuhne wrote:
> Am 16.08.2010 12:44, schrieb Pasi Kärkkäinen:
> > On Mon, Aug 16, 2010 at 12:15:41PM +0200, Stefan Kuhne wrote:
> 
> Hello Pasi,
> 
> >> On 64bit system boots until mount of rootfs.
> >>
> > 
> > So does 64bit kernel boot/work OK?
> > 
> I think so.
> But command line forgot "root=..." and I don't know why.
> 

Sounds like you're using GRUB2.

See: http://wiki.xensource.com/xenwiki/XenCommonProblems

It's a known issue. Xen 4.0.1-rc6 has that fixed. 
If you use Xen 4.0.1-rc5 or older version you need to add "dummy=dummy" 
as the first parameter to grub config. It's explained in the wiki page above.

> >> But 32bit boots until:
> >> (XEN) d0:v0: unhandled page fault (ec=0009)
> >> (XEN) Pagetable walk from c009fc00:
> >> (XEN)  L3[0x003] = 0000000039820001 00001820
> >> (XEN)  L2[0x000] = 0000000039fdd067 00001fdd
> >> (XEN)  L1[0x09f] = 000007fffffff063 ffffffff
> >> (XEN) d0:v0: reserved bit in page table (ec=0009)
> >>
> >> Is anybody running an 32bit System?
> >> I need 32bit because of my destination Distro is only in 32bit available.
> >>
> > 
> > Based on the full bootlog the problem is in the dom0 kernel, not in Xen 
> > hypervisor.
> > Did you try earlier versions of the dom0 kernel? Which version introduces 
> > this problem?
> > 
> Only 2.6.13.14 from xen-4.0.1-rc5.
> 
> > I think 2.6.32.10 booted/worked for me on 32bit..
> > 
> How can I get this version?
> 

You should be able to use something like this:

git clone git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git 
linux-2.6-xen
cd linux-2.6-xen
git checkout -b xen/stable-2.6.32.x origin/xen/stable-2.6.32.x
git checkout fe6e0879f323b2352aae9dddbb2b253334e10d6c

That should give you 2.6.32.10 .. just before 2.6.32.11 merge.
I haven't tested/tried that exact version myself,
so choose some other version from some other date if it doesn't work.

Use the online changelog browser to browse through the changelog,
and then open some 'commit' message to get the commit id for "git checkout":
http://git.kernel.org/?p=linux/kernel/git/jeremy/xen.git;a=shortlog;h=xen/stable-2.6.32.x


> > 
> > <snip>
> > 
> >> [    0.000000] NX (Execute Disable) protection: active
> > 
> > 
> > Did you try without NX? (ie. turn it off in the BIOS). 
> > 
> I've tested a lot.
> I'll try it again.
> 

Ok.

> >> [    0.000000] 302MB HIGHMEM available.
> >> [    0.000000] 721MB LOWMEM available.
> > 
> > Does dom0_mem=512M help? 
> > 
> I'll test it.
> 

Yep.

> >> (XEN) d0:v0: unhandled page fault (ec=0009)
> >> (XEN) Pagetable walk from c009fc00:
> >> (XEN)  L3[0x003] = 0000000039820001 00001820
> >> (XEN)  L2[0x000] = 0000000039fdd067 00001fdd
> >> (XEN)  L1[0x09f] = 000007fffffff063 ffffffff
> >> (XEN) d0:v0: reserved bit in page table (ec=0009)
> >> (XEN) Pagetable walk from c009fc00:
> >> (XEN)  L3[0x003] = 0000000039820001 00001820
> >> (XEN)  L2[0x000] = 0000000039fdd067 00001fdd
> >> (XEN)  L1[0x09f] = 000007fffffff063 ffffffff
> >> (XEN) ----[ Xen-4.0.1-rc6  x86_32p  debug=n  Tainted:    C ]----
> >> (XEN) CPU:    0
> >> (XEN) EIP:    e019:[<c17a56a1>]
> > 
> > You'd have to use gdb on the kernel vmlinux file to resolve which
> > funtion this address points to.. to see why/where it crashes.
> > 
> I never has debugged a Kernel.
> 

Go to the source tree directory where the dom0 kernel was compiled 
(it needs to be the exact source tree for the kernel you boot).

And run:
gdb vmlinux

Then execute the following commands:
(gdb) x/i 0xc17a56a1
(gdb) list *0xc17a56a1

(c17a56a1 is the EIP value from the crashlog).

And paste the output here.

-- Pasi



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