Problem loading with newly compiled kernel

[josolanes]

This is my first time compiling a kernel and it seemed to go very smoothly, but now my computer won't load using this kernel. The error I get is:

VFS: Cannot open root device "ram0" 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)

I think it has to do with my grub.conf, but I copied the other kernel's info and adjusted the file names (image file and kernel) for my new kernel. I think that's what I was supposed to do. When I try loading the system with the new kernel it'll load a lot of devices and show a lot of text on the screen, but stop and show the above error message.

Can someone please help me with this?

[josolanes]

I think I found the solution (about 10 threads down)

I searched but didn't come up with anything, but ran into it by accident.

[josolanes]

I have another problem now...can someone please help me with this? Here's the error message:

Creating block devices
failed to create /dev/hda
failed to create /dev/hda1
failed to create /dev/hda2
failed to create /dev/hda3
Creating root device
mkrootdev: mkroot failed: 30
Mounting root filesystem
mount: error 2 mounting reiserfs
pivotroot: pivot-root (/sysroot, /sysroot/iniitrd) failed: 2
umount /initrd/proc failed: 2
Kernel panic - not syncing: Attempted to kill init!

Please help...this is driving me crazy.

[Salient]

I think it has to do with my grub.conf, but I copied the other kernel's info and adjusted the file names (image file and kernel) for my new kernel. I think that's what I was supposed to do

*A FRIENDLY TIP*
Using Grub you don't have to delete your original kernel entry and replace it with the new kernel entry - With Grub you can choose at bootup which kernel you want to load. I actually leave the old kernel entry in case my new kernel has problems ... if it does then i can select the original kernel at boot and my system is back to normal.

Once your sure the new kernel is the one you wan't to keep edit the line (in boot/grub/menu.1st) from default=0 to default=1

As far as the errors go ... If your using the Ext 3 file system make sure you're .config has the following in it: CONFIG_EXT3_FS=y
You'll run into the following error if you leave this =m instead of =y:
pivotroot: pivot_root(/sysroot,/sysroot/initrd) failed
This is because the ext3 filesystem is used for /boot ...

[michael138uk]

hi

i've looked at the forum, but i cannot find the solution to the following error

VFS: Cannot open root device "ram0" 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)

U said that u had found it, please would be so kind as to tell me how to solve it

thanks

[LinuxExpert]

pivotroot: pivot_root(/sysroot,/sysroot/initrd) failed

The solution to this is to boot with a rescue CD, mount the root file system and run the command 'mkdir initrd'. After this, reboot your system.

Pivotroot is a command run by the initrd (initial RAM disk). First, Linux boots with the initrd as root, with the normal root disk mounted under /sysroot (readonly). At the end of the boot of the initrd, the command pivotroot is run, that switches the initrd root disk with the normal root disk. The problem is that /initrd is then used as a mount point (/sysroot/initrd), and if the directory does not exist, it will fail. If it has been deleted by mistake, it is very difficult to realize that this is the problem.

[raulka]

Josolanes, Michael it would be nice to know which version of the kernel you are trying to load.
If it is 2.6.22 and probably higher, your initrd must refer to a cramfs filesystem that is then loaded into the ram drive instead of old initrd.

Download mkcramfs and use:
mkcramfs -b 4096 /boot cramfs.img
/boot should contain you kernel, initrd.img etc.
cramfs.img is just name of the file into which /boot directory is compressed in cramfs format - could be any name. Then use that instead or initrd.