Xen users - Jan 2012 - Kernel panic on Xen dom0 vanilla kernel: No init found.

Hello,

I''m currently installing Xen on the latest Gentoo Linux and
i''m having some
trouble to boot the dom0 kernel. It starts the xen.gz kernel, switches to
the linux kernel module and fails to find /sbin/init. I''m using the
kernel
vanilla sources from kernel.org:
http://git.kernel.org/?p=linux/kernel/git/konrad/xen.git;a=summary

The console output from the kernel does not really give any useful
information:

(...)
EXT4-fs (sda3): mounted filesystem with ordered data mode (null)
VFS: Mounted root (ext4 filesystem) on device 8:3.
(...)
Kernel panic - not syncing: No init found. Try passing init= option to
kernel.

... and the usual panic call trace.

When i boot the same kernel without xen.gz on the same filesystem, it boots
fine. Here is my /boot/grub/grub.conf:

# Fails to boot, no init found.
title Gentoo Linux 3.1.0-rc10-xen with Xen
root (hd0,0)
kernel /xen.gz dom0_mem=128M
module /boot/kernel-3.1.0-rc10-xen root=/dev/sda3 ro

# Boots fine.
title Gentoo Linux 3.1.0-rc10-xen
root (hd0,0)
kernel /boot/kernel-3.1.0-rc10-xen root=/dev/sda3

I also did some research found and someone had this error while booting a
domU: http://lists.xen.org/archives/html/xen-users/2009-04/msg00662.html. I
double-checked my .config to verify that I have the CONFIG_IA32_EMULATION
option enabled .

Does anyone spot the problem?

-----------------------------
Additional info:

My kernel config file: http://pastebin.com/Vn7XwJRV

Xen installation:

# emerge -av net-misc/bridge-utils dev-python/pyxml dev-perl/sdl-perl
sys-apps/iproute2 sys-apps/pciutils app-text/texi2html dev-libs/libaio
app-arch/bzip2 media-gfx/transfig git dev86 iasl mercurial
# hg clone http://xenbits.xen.org/xen-4.1-testing.hg
# cd xen-4.1-testing.hg
# make PYTHON=python2 xen
# make PYTHON=python2 tools
# make PYTHON=python2 stubdom
# make PYTHON=python2 install-xen
# make PYTHON=python2 install-tools
# make PYTHON=python2 install-stubdom

System / file info:

# uname -a
Linux VSERVER 3.1.0-rc10-xen+ #1 SMP Sun Jan 15 21:37:47 CET 2012 x86_64
Intel(R) Core(TM) 2 Quad CPU Q8400 @ 2.66GHz GenuineIntel GNU/Linux

# file /sbin/init
/sbin/init: ELF 64-bit LSB executable, x86-64, version 1 (SYSV),
dynamically linked (uses shared libs), for GNU/Linux 2.6.9, stripped

# gunzip xen.gz
# file xen
xen: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), statically
linked, stripped

# file /boot/kernel-3.1.0-rc10-xen
/boot/kernel-3.1.0-rc10-xen: Linux kernel x86 boot executable bzImage,
version 3.1.0-rc10-xen+ (root@livecd) #1 SMP Sun Jan 15 21:37:47 CET 20,
RO-rootFS, swap_dev 0x5, Normal VGA


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On Tue, Jan 17, 2012 at 10:29:27PM +0100, Johan Gielens
wrote:
> # Fails to boot, no init found.
> title Gentoo Linux 3.1.0-rc10-xen with Xen
> root (hd0,0)
> kernel /xen.gz dom0_mem=128M
> module /boot/kernel-3.1.0-rc10-xen root=/dev/sda3 ro
> 
I don''t really have much to suggest but what happens if you pass
init=/bin/bash?  Also, is
128M enough for the dom0 and you are encountering an oom error, if you pass
1024m for the
sake of testing does it work?

James

When I pass init=/bin/bash to the kernel it also doesn''t work. About
the
dom0_mem: 128M is the suggested default. Passing dom0_mem=1024M to the
kernel gives the same result, but the kernel has some configuration about
this too.

I suspect there is something wrong with Xen being 32 bit and my kernel and
filesystem 64 bit.
Is there something else I could try?

Johan

2012/1/18 James Dingwall <james@dingwall.me.uk>
> On Tue, Jan 17, 2012 at 10:29:27PM +0100, Johan Gielens wrote:
> > # Fails to boot, no init found.
> > title Gentoo Linux 3.1.0-rc10-xen with Xen
> > root (hd0,0)
> > kernel /xen.gz dom0_mem=128M
> > module /boot/kernel-3.1.0-rc10-xen root=/dev/sda3 ro
> >
>
> I don''t really have much to suggest but what happens if you pass
> init=/bin/bash?  Also, is
> 128M enough for the dom0 and you are encountering an oom error, if you
> pass 1024m for the
> sake of testing does it work?
>
> James
>

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