[SOLVED] Boot problem after installing Ubuntu 11.04 - "Kernel panic

mvmannheim · 12-16-2011, 08:48 PM

So I upgraded to Ubuntu Desktop v12.04. After doing so, I'm unable to boot the machine.

The complete error message is:

Code:

"Kernel panic - not syncing VFS; Unable to mount root fs on unknown-block(0,0)"

followed by some address and register data, I assume...

Somehow, I think GRUB isn't getting found/loaded.

I'm able to load the install CD and run a terminal as root. All of my files are in /home and it looks like the root partition is ok.

The fstab file looks like:

Code:

proc		/proc		proc		defaults		0		0
# /dev/sda1
UUID…   	/   		ext3    realtime,errors=remount-ro     0        1
# /dev/sda5
UUID… 	none		swap		sw			0		0
/dev/scd0	/media/cdrom0…
/dev/fd0		/media/floppy0…

If I run> parted -l:
Model: ATA HTS…(scsi)
Disk /dev/sda: 40.0GG
Sector size (logical/physical): 512B/512B
Partition table: msdos

Code:

Number	Start	End		Size		Type		File System		Flags
1		32.5kB	38.5GB	38.5GB	primary	ext3				boot
2		38.5GB	40.0GB	1546GB	extended
5		38.5GB	40.0GB	1546GB	logical	linux-swap(v1)

Warning: Unable to open /dev/sr0 read-write (Read-only file system). /dev/sr0 has been opened read-only. Error: Can't have a partition outside the disk!

If I run> parted check 2
or
> parted rm 2

Code:

Error: could not stat device check - No such file or directory

It seems that somehow the partitions 2 & 5 are beyond the size of the hard drive (40.0GB), but I don't know how to fix that.

Any ideas would be greatly appreciated!

business_kid · 12-17-2011, 03:21 AM

That error means it found the kernel but not the root filesystem.

Looking at fstab, this is wrong
# /dev/sda1
UUID… / ext3 realtime,errors=remount-ro 0 1

You need the UUID, or, simpler, put in sda1 for that one instead of UUID...

You can find UUIDs in /dev/disk/by-uuid or suchlike place. Do similarly fo0r swap.

mvmannheim · 12-17-2011, 12:02 PM

business_kid - thanks for the reply. Actually, I intentionally shortened the UUID for the post. In reality the fstab file contains the full UUIDs in each case.

business_kid · 12-18-2011, 11:06 AM

OK - uuid is not the problem.

Here's my line from /boot/grub/menu.lst

Quote:

title Slackware-13.1-2.6.38.4-xxx Kernel
root (hd0,4)
kernel /vmlinuz-2.6.38.4-xxx root=/dev/sda8 ro resume=/dev/sda9 pcie_aspm=force

This is a poor example, because the partition numbers are all over the shop. But that highlighted option tells the kernel where to look for the root filesystem, and it needs to find / there. Your setting there must be wrong. So the kernel looks in the wrong place and says "Hey, that's not a root filesystem", and spouts the error you saw.

mvmannheim · 12-18-2011, 02:34 PM

business_kid - thanks so much for your help! That did it! For some reason my menu.lst file had the root parameter set to root=UUID=7395...

After setting root=/dev/sda1 everything boots swimmingly.

Much appreciated!