Initramfs error during boot

[Sertaç Olgunsoylu]

Hi all,
I built stable tree and latest(linus' tree) with default configuration
and then installed them on my laptop. However, when I try to boot my
system with kernels that I built, it cannot boot. It freezes just
after selection made on GRUB and nothing is printed on the display. I
managed to get following error by booting system in recovery mode:

Starting up ...
mount: mounting /dev/disk/by-uuid/48bfb57f-4750-4537-b563-7094743c161e on /root
failed: Invalid argument
mount: mounting /dev on /root/dev failed: No such file or directory
mount: mounting /sys on /root/sys failed: No such file or directory
mount: mounting /proc on /root/proc failed: No such file or directory
Target filesystem doesn't have requested /sbin/init.
No init found.  Try passing init= bootarg.

I build kernel with following commands:
make O=../build defconfig
make O=../build -j2
sudo make O=../build modules_install install

You could see grub.cfg entries below for both (custom build kernel and
stock build kernel):

# Custom build
menuentry 'Ubuntu, with Linux 3.2.7' --class ubuntu --class gnu-linux
--class gnu --class os {
        recordfail
        set gfxpayload=$linux_gfx_mode
        insmod gzio
        insmod part_msdos
        insmod ext2
        set root='(hd0,msdos3)'
        search --no-floppy --fs-uuid --set=root
48bfb57f-4750-4537-b563-7094743c161e
        linux   /boot/vmlinuz-3.2.7
root=UUID=48bfb57f-4750-4537-b563-7094743c161e ro   quiet splash
vt.handoff=7
        initrd  /boot/initrd.img-3.2.7
}

# Stock build
menuentry 'Ubuntu, with Linux 3.0.0-16-generic' --class ubuntu --class
gnu-linux --class gnu --class os {
        recordfail
        set gfxpayload=$linux_gfx_mode
        insmod gzio
        insmod part_msdos
        insmod ext2
        set root='(hd0,msdos3)'
        search --no-floppy --fs-uuid --set=root
48bfb57f-4750-4537-b563-7094743c161e
        linux   /boot/vmlinuz-3.0.0-16-generic
root=UUID=48bfb57f-4750-4537-b563-7094743c161e ro   quiet splash
vt.handoff=7
        initrd  /boot/initrd.img-3.0.0-16-generic
}