Re: Kernel Panic

[Douglas Tutty <dtutty@porchlight.ca>]

On Wed, Dec 13, 2006 at 11:10:02AM -0500, Morgan Walker wrote:
> After updating to 2.6.16-2-amd64-k8-smp on my Sun X4100 I rebooted and
> got the following error:
> 
> VFS: Cannot open root device md0 or unknown-block(0,0)
> 
> Please append a correct "root=" boot option
> 
> Kernel Panic - not syncing: VFS: Unable to mount root fs on
> unknown-block(0,0)
> 
> And this is where it will stop during the boot process.  I am running a
> RAID1 on this machine.  When the screen comes up to choose which kernel
> I want to boot, I press "e" to edit the grub/menu.list, but all looks
> well.  Here is what I have:
> 
> root            (hd0,0)
> kernel          /boot/vmlinuz-2.6.16-2-amd64-k8-smp root=/dev/md0 ro
> initrd          /boot/initrd.img-2.6.16-2-amd64-k8-smp
> savedefault
> 
> I'm stumped, what options do I have?
> 

Hi Morgan
 
Is the problem that the kernel can't read the filesystem on the raid1
md0 block device or that it can't find the block device?  The initramfs
should take care of loading any modules required so you shouldn't have
to recompile the kernel.

You could try editing that root= line to point directly to one of the
disks (and add init=/bin/sh to avoid doing anything other than testing
the kernel).  If this works, it means that the kernel is not handling
your raid setup; if it doesn't it means the problem is not the raid
setup.

My hunch is that in the process of updating the kernel that the initrd
didn't get made right.  If the above suggestion doesn't get you back in,
and you don't have a previous kernel installed to boot, you can boot
your installer media in rescue mode.

Once into you system, try dpkg-reconfigure the kernel package involved.
I say to do this instead of manually running mkinitrd (or initramfs)
since I don't know what parameters it needs; that's the job of the
kernel post-inst.

Good luck.

Doug.