Changed Linux Kernel

I have had the Arch Linux linux-hardened kernel installed on my Qotom fanless server since I bought it a couple of years ago. The Qotom has had kernel panics on the last two linux-hardened updates. I changed to the plain linux kernel. It was pretty easy, even though I had a case of the nerves about it.

Arch Linux, a simple, lightweight Linux distribution, offers several alternative kernels. All the alternatives are Linux, just compiled with different options and maybe some patches. I typically run linux-hardened on any server that has direct internet access, There’s linux-zen, supposedly optimized for performance and interactive snappiness. I’ve superstitiously run it on several generations of Dell laptop because some years ago, linux-zen fixed an all black screen on a Dell. There’s linux-lts, which is the official long term support kernel. I think it’s a good idea to run software of any sort that’s not quite the mainstream, to avoid a software monoculture. I’m doing my part, although if I took this far enough, I’d be running NetBSD like I did back in the mid-1990s.

After fixing a kernel panic in 2 successive versions of linux-zen, I decided to put another kernel on the Qotom. I’ve done this process several times over the years. I can’t recall it ever being more than minimal hassle, but I’m nervous about it every time. This time, it was also a simple process. It only took about 10 minutes, and half of that was triple-checking all commands.

The Actual Commands

These commands are very Arch Linux specific, but I imagine similar things would work with other distros.

1. sudo pacman -R linux-hardened linux-hardened-headers
2. sudo pacman -S linux linux-headers
3. sudo mv grub.cfg old.grub.cfg
4. sudo grub-mkconfig -o /boot/grub/grub.cfg
5. sudo vim grub.cfg
   • remove “quiet” from 2 invocations of /vmlinuz-linux so I can see what goes on at boot.
6. sync;sync;sync;sudo systemctl reboot

Just to be very specific, the Qotom experienced a kernel panic with the Arch Linux linux-hardened kernel package, versions 7.1.5.hardened1-1 and 7.1.5.hardened1-3. I have had panics of updated kernels happen maybe twice before. I did nothing to figure out what the cause was. Backing off to version 7.1.3.hardened1-4 worked, so I figured there’s just some specific weirdness in the linux-zen kernel causing it.