[SOLVED]Unable to boot into the kernel I compiled, kernel panic

Question

I try to compile a kernel myself and boot into it, and I use virtualbox to test it. (arch guest inside my arch host)  I first copy /proc/config.gz of my guest system to the linux source code directory, rename it to .config, and just compile it. After that I copy the image under arch/x86/bzImage to /boot directory, then I follow the instruction given by the arch wiki to create an entry in grub. Here is my /etc/grub.d/40-custom:
#!/bin/sh
exec tail -n +3 $0
menuentry 'Custom Entry' {
set root=(hd0,msdos1)
echo 'Loading Modified Linux'
linux /boot/vmlinuz-modified
echo 'Loading initial ramdisk ...'
initrd /boot/initramfs-linux.img
following is this command:
grub-mkconfig -o /boot/grub/grub.cfg
But after reboot I cannot boot into the new kernel, it shows "unable to mount root fs on unknown-block(0,0):
https://img.vim-cn.com/e5/5227d8d4cc07c … ce81ee.png (choose "Advanced Option for Archlinux-> With Linux Modified")
https://img.vim-cn.com/a9/12869edfbbca1 … 649380.png (choose "Custom Entry" on the first page directly)
I have searched for a while but didn't find a solution. Is there anything I'm doing wrong, please?
Last edited by Frefreak (2015-05-07 10:48:05)

Answer 1

Head_on_a_Stick wrote:
Frefreak wrote:I think I did compress it, if I remember correctly. (I actually built it several times)
I am referring to /proc/config.gz -- this is a gzip archive and needs to be decompressed before you can use it to compile your kernel image.
This isn't strictly true, it just makes the process easier because you're starting with a sane .config (assuming you're booted into one of Arch's official kernels at least). You can start from scratch, but you need to know what you're doing.
Frefreak wrote:Ok, I'll rebuild everything from the beginning later.
No need to rebuild everything, just generate an initramfs for the custom kernel. The initramfs contains modules that are specific to a the kernel image that they were generated for; this is probably why /boot/initramfs-linux.img isn't working for you.