Ubuntu

Kernel Panic -- It was working earlier (I think I messedup something)

Asked by Ajay

I have recently upgraded from 7.04 to 7.10.

The booting was working well with '/boot/vmlinuz-2.6.22-14-generic'. The only problem I had was with the screen at the start becoming blank for a good 2 to 3 mins.
I had seen this problem earlier when I had installed 7.04 using the live cd.
Now to fix this issue earlier I had used Startup-Manager.
I do not remember the resolution and depth that I had selected that had solved my splash screen problem earlier. Hence I was trying all different combinations of resolutions one after the other. In an attempt to speed up my 'boot->change config->reboot' steps, I think in my last attempt I did not give 'Startup-Manager' enough time to write back the values into initramfs.
My guess is that this might have messedup the image file.
After this I have not been able to reboot using 'vmlinuz-2.6.22-14-generic'. I have always had to boot using 'vmlinuz-2.6.20-16-generic' (which seems to be in proper shape).

I keep getting Kernel panic when I try with 'vmlinuz-2.6.22-14-generic'.
Can someone suggest a way in which I can restore my corrupt files and regenerate the image?

Also is there a way to get the kernel panic messages in some log file, so that I could put it up for people to look at? I can't find any entry for the kernel panic boot in the file '/var/log/kernel.log'....not sure if that is the right place to look out?

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Ajay (ajay-g-m) said : 		#1

The following are the lines that I could note down before the kernel panic....

----------------------------------------------------------------
[ 17.xxxx] Switched to high resolution mode on CPU0
[ 18.xxxx] VFS: Cannot open root device "UUID=xxxxxxxxxxxxxxxxxxx" or unknown-block (0,0)
[ 18.xxxx] Please append a correct "root=" boot option; here are the available partitions:
[ 18.xxxx] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block (0,0)
----------------------------------------------------------------

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Ajay (ajay-g-m) said : 		#2

The following help me resolve the issue....

Boot into the live CD, open the terminal, and run:

-------------------------------------------
mkdir /mnt/linux
mount /dev/hda1 /mnt/linux
chroot /mnt/linux /bin/bash
mount -t proc /proc /proc
sudo update-initramfs -u
-------------------------------------------
I got this info from 'http://ubuntuforums.org/showpost.php?p=1711279&postcount=2'.

In the above process we require a live CD. I was lucky that I had a live CD from one of my friends.

Just out of curiosity was wondering if there is any way to achieve the same using the alternate CD?

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marcobra (Marco Braida) (marcobra) said : 		#3

I think yes but never tried the above commands, pressing CTRL+ALT+F2 or CTRL+ALT+F3 you can get terminal access and you can try the above terminal shell commands.

Hope this helps

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Bhavani Shankar (bhavi) said : 		#4

Could you please boot up into recovery mode (usually the 2nd option in grub menu) and paste output of

fdisk -l

Regards

Bhavani Shankar.

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