Kernel panic after upgrade

[Jonas Norlander]

On Tue, Aug 11, 2009 at 8:09 AM, Nils Kassube<kassube at gmx.net> wrote:
> Mark Halegua wrote:
>> [ 2.024321] Kernel panic - not syncing VFS: Unable to mount root fs
>> on unknown - block(0,0)
>>
>> Never had to troubleshoot a kernel panic before.  Is this having
>> trouble with grub, or is the menu.lst entry incorrect in some way?
>> The partition the root directory (and the subdirectory /boot) in hda5
>> and the root entry for the vmlinux kernel in the menu.lst is (hd0,4)
>
> To me it looks like grub can find the kernel and has started it. But the
> kernel can't find the root device. Maybe there is a problem with the
> kernel line in the grub menu. It should be something like this:
>
> kernel /boot/vmlinuz-2.6.28-14-generic root=UUID=c8170ac2-
> d4a1-4edb-82f5-83c9f7c86c7e ro quiet splash
>
> If you don't have a UUID but something like "root=/dev/hda5" this may be
> the problem because it isn't guaranteed that disks always have the same
> device name (if you have more than one disk).

Disk devices is not named hda anymore, its sda for some kernel versions back.
If your root was on hda5 try to replace it with sda5 in grub. The best
way is as Nils wrote to use UUID for al your partitions.

/ Jonas