Bad luck with a buggy Linux kernel

Posted on Sat 23 December 2023 in Linux

When I installed Debian on a Thinkpad two weeks ago, I was out of luck. As you may have heard, the stable Linux kernel maintenance team imported a change from the upstream which caused a major problem on systems with ext4 filesystems. Ext4 is the default for Debian installs, and many other distributions rely on this stable file system. When the problem was discovered, the Debian team blocked the package very quickly. Unfortunately, my new setup on a Thinkpad already had the affected kernel version installed.

Normally this would not have affected me, as I have been using XFS on most of my machines for years. Again, I just used the Debian installer defaults, because I am getting lazy and had bad luck with them.

But why did I reinstall the Thinkpad at all? To cut a long story short, the first installation was a test run of Debian on the Thinkpad and I did not encrypt the root partition. All my mobile systems have encrypted harddisks, and as I plan to use this machine as a as a travelling and conferencing system, it needed an encrypted disk setup as well.

For me, only one machine was affected by this broken kernel version, and all the other servers do not install updates or reboot themselves to apply a new kernel version for this reason. It is very rare for a bug like this to occur, but it happens often enough that I want to have control over my update procedures. If I had installed this kernel on all my machines, I would have had a real problem, as most of the virtual machines I run use ext4. It would have meant checking all the machines for data corruption or restoring them from backup, to make sure the data was not corrupted. Not a scenario I want to be in.

By the way, I have to admit that the Debian installer is very mature these days. Even setting it up with an encrypted disc and changing the type of file system was straightforward. Now the Thinkpad has an encrypted hard drive, runs the latest Debian and uses XFS as the root filesystem. Everything works fine and this notebook will be my travelling companion and conference tool.