I have a ridiculous amount of kernels

In previous blogposts I wrote about how I found a possible bug in the Linux kernel, or more precisely, in the kernel that Ubuntu derived from the mainline kernel.

• Part 1: Discovering the bug
• Part 2: Installing mainline kernels
• Part 3: Compiling kernels from source
• Part 4: Using git bisect

To be able to install any kernel version 5.15.7 or higher, I also had to install libssl3.

The result is that I now have 37 kernels installed, taking up little over 2 GiB disk space:

$ (cd /boot ; ls -hgo initrd.img-* ; ls /boot/initrd.img-* | wc -l)
-rw-r--r-- 1 39M mrt  9 09:54 initrd.img-5.13.0-051300-generic
-rw-r--r-- 1 40M mrt  9 09:58 initrd.img-5.13.0-19-generic
-rw-r--r-- 1 40M mrt  9 09:58 initrd.img-5.13.0-20-generic
-rw-r--r-- 1 40M mrt  9 09:57 initrd.img-5.13.0-21-generic
-rw-r--r-- 1 44M mrt 30 17:46 initrd.img-5.13.0-22-generic
-rw-r--r-- 1 40M mrt  9 09:56 initrd.img-5.13.0-23-generic
-rw-r--r-- 1 40M mrt  9 09:56 initrd.img-5.13.0-25-generic
-rw-r--r-- 1 40M mrt  9 09:56 initrd.img-5.13.0-27-generic
-rw-r--r-- 1 40M mrt  9 09:55 initrd.img-5.13.0-28-generic
-rw-r--r-- 1 40M mrt  9 09:55 initrd.img-5.13.0-30-generic
-rw-r--r-- 1 45M mrt  9 12:02 initrd.img-5.13.0-35-generic
-rw-r--r-- 1 45M mrt 24 23:17 initrd.img-5.13.0-37-generic
-rw-r--r-- 1 45M mrt 30 17:49 initrd.img-5.13.0-39-generic
-rw-r--r-- 1 39M mrt  9 09:54 initrd.img-5.13.1-051301-generic
-rw-r--r-- 1 39M mrt  9 09:54 initrd.img-5.13.19-051319-generic
-rw-r--r-- 1 37M mrt  9 09:53 initrd.img-5.13.19-ubuntu-5.13.0-22.22
-rw-r--r-- 1 37M mrt  9 09:53 initrd.img-5.13.19-ubuntu-5.13.0-22.22-0-g3ab15e228151
-rw-r--r-- 1 37M mrt  9 09:52 initrd.img-5.13.19-ubuntu-5.13.0-22.22-317-g398351230dab
-rw-r--r-- 1 37M mrt  9 09:52 initrd.img-5.13.19-ubuntu-5.13.0-22.22-356-g8ac4e2604dae
-rw-r--r-- 1 37M mrt  9 09:52 initrd.img-5.13.19-ubuntu-5.13.0-22.22-376-gfab6fb5e61e1
-rw-r--r-- 1 37M mrt  9 09:51 initrd.img-5.13.19-ubuntu-5.13.0-22.22-386-gce5ff9b36bc3
-rw-r--r-- 1 37M mrt  9 09:51 initrd.img-5.13.19-ubuntu-5.13.0-22.22-387-g0fc979747dec
-rw-r--r-- 1 37M mrt  9 09:50 initrd.img-5.13.19-ubuntu-5.13.0-22.22-388-g20210d51e24a
-rw-r--r-- 1 37M mrt  9 09:50 initrd.img-5.13.19-ubuntu-5.13.0-22.22-388-gab2802ea6621
-rw-r--r-- 1 37M mrt  9 09:50 initrd.img-5.13.19-ubuntu-5.13.0-22.22-391-ge24e59fa409c
-rw-r--r-- 1 37M mrt  9 09:49 initrd.img-5.13.19-ubuntu-5.13.0-22.22-396-gc3d35f3acc3a
-rw-r--r-- 1 37M mrt  9 09:49 initrd.img-5.13.19-ubuntu-5.13.0-22.22-475-g79b62d0bba89
-rw-r--r-- 1 37M mrt  9 09:48 initrd.img-5.13.19-ubuntu-5.13.0-23.23
-rw-r--r-- 1 40M mrt  9 09:48 initrd.img-5.14.0-051400-generic
-rw-r--r-- 1 40M mrt  9 10:31 initrd.img-5.14.21-051421-generic
-rw-r--r-- 1 44M mrt  9 12:39 initrd.img-5.15.0-051500-generic
-rw-r--r-- 1 46M mrt  9 12:16 initrd.img-5.15.0-22-generic
-rw-r--r-- 1 46M mrt 28 23:27 initrd.img-5.15.32-051532-generic
-rw-r--r-- 1 46M mrt 17 21:12 initrd.img-5.16.0-051600-generic
-rw-r--r-- 1 48M mrt 28 23:19 initrd.img-5.16.16-051616-generic
-rw-r--r-- 1 45M mrt 28 23:11 initrd.img-5.17.0-051700-generic
-rw-r--r-- 1 46M apr  8 17:02 initrd.img-5.17.2-051702-generic
37

• Versions 5.xx.yy-zz-generic are installed with apt.
• Versions 5.xx.yy-05xxyy-generic are installed with the Ubuntu Mainline Kernel Installer.
• Versions 5.xx.yy-ubuntu-5.13.0-zz.zz-nnn-g<commithash> are compiled from source, where <commithash> is the commit of the kernel repository that I compiled.

The kernels in bold are the kernels where something unexpected happens with my USB devices:

• Ubuntu kernels 5.13.23 and up – including 5.15 kernels of Ubuntu 22.04 LTS (Jammy Jellyfish).
• Ubuntu compiled kernels, starting 387 commits after kernel 5.13.22.
• Mainline kernels 5.15.xx.

When Ubuntu finally bases their kernel on mainline 5.16 or higher, then the USB bug will be solved.