Arch Linux

taylskid

Member

Registered: 2016-10-28

Posts: 1

mkinitcpio & cutom kernel question

Hello,

I built and successfully booted a kernel built from the git src last night, but ran into one particular issue that I'm hoping someone here can clear up. I built and installed the kernel in a relatively straightforward way:

make clean && make mrproper
make localmodconfig
make nconfig 
make
sudo make modules_install
sudo cp -v arch/x86_64/boot/bzImage /boot/vmlinuz-linux490
sudo mkinitcpio -k 4.9.0-rc2-ARCH-00138-g14970f2 -g /boot/initramfs-linux490.img
sudo grub-mkconfig -o /boot/grub/grub.cfg

The only thing I changed in the config was I disabled CONFIG_MODVERSIONS as suggested here: https://bbs.archlinux.org/viewtopic.php … 5#p1664375

All of these commands ran without a hitch, but every time I tried to boot the new kernel, it would start booting, and complain about not being able to find the root device UUID. When it sent me to the emergency shell, I could not type on the keyboard. I tried this on a physical machine as well as a VM and got the same problem both times.

Finally I found a post suggesting swapping udev for systemd in the hooks of mkinitcpio.conf, which I did, regenerated the initramfs for my kernel, rebooted, and it booted fine:

[taylor@demeter ~]$ uname -a
Linux demeter 4.9.0-rc2-ARCH-00138-g14970f2 #1 SMP PREEMPT Fri Oct 28 02:54:55 EDT 2016 x86_64 GNU/Linux

I regenerated the initramfs for the stock kernel as well (just with mkinitcpio -p linux), and it still booted after swapping from udev to systemd.

So my question is this: I've spent a considerable amount of time shopping around for answers, and I cannot seem to find any. Why does systemd hook work for both kernels, where udev _only_ worked for the stock kernel? Any suggestions would be super helpful, I appreciate it.