bug#54010: Linux-libre > 5.15.12 leads to unbootable system

[Ludovic Courtès]

2022 has left me without a working Linux-libre kernel.

Breakage occurred sometime between:

  • 92faad0adb93b8349bfd7c67911d3d95f0505eb2
    (Jan. 3rd; Linux-libre 5.15.12)

  • 43dd34c7777a212c99a97da7a2c237158faa9a1b
    (Jan. 31st; Linux-libre 5.15.17)

The symptoms are that, on my x86_64 laptop, the kernel boots, I can
enter the passphrase for my root file system (‘cryptsetup’ is invoked
from the initrd), things get printed, the console font changes, and then
things get stuck here.  The last messages are from my sound card driver
(Intel HDA).  It hangs before syslogd is started, and I think before
shepherd is even started (I can’t be 100% sure because I cannot scroll
back at that point, but I did add print statements in ‘shepherd.conf’
and didn’t see them.)

The same config works in ‘guix system vm’.

I can work around the problem by reconfiguring from current ‘master’ and
doing this:

--8<---------------cut here---------------start------------->8---
(define inferior-for-kernel
  (inferior-for-channels
   (list (channel
          (name 'guix)
          (url "https://git.savannah.gnu.org/git/guix.git";)
          (commit
           "92faad0adb93b8349bfd7c67911d3d95f0505eb2")))))

(operating-system
  ;; …
  (kernel
    (first (lookup-inferior-packages inferior-for-kernel "linux-libre"))))
--8<---------------cut here---------------end--------------->8---

This suggests a kernel issue.

Ideas and suggestions on how to debug this most welcome!

Ludo’.