Bug#948921: linux-image-5.4.0-2-amd64: decrypting root partition does not work on 5.4.0 (works on 5.3.0) with decrypt_keyctl

[Luc Maisonobe <luc@spaceroots.org>]

Here are some additional informations about the problem.

I rechecked it was not a keyboard layout problem by setting up
an additional luks key, a very short one that used only keys that
were at the same position in both qwerty and azerty. It does
not work, so it's definitely not a keyboard problem.

The error I get on boot is as follows:

  Caching passphrase for sdb1_crypt:***********************
  [  15.212421] device-mapper: table: 253:0: crypt: Error allocating
crypto tfm
  device-mapper: reload ioctl on   failed: No such file or directory
  cryptsetup: ERROR: sdb1_crypt: cryptsetup failed, bad password or options?

  Caching passphrase for sdb1_crypt:

I tried to use a key file instead of a key typed by user just
like I did on the other laptop. I do not want to use this method
for  this specific machine for security reasons (it should not be
abel to boot unattended), but tried it temporarily. I regenerated
the initramfs after changing the /etc/crypttab file, but it didn't
work either. When generating initramfs, I got the following warning,
so it may explain why it didn't work.

  cryptsetup: WARNING: Skipping root target sdb1_crypt: uses a key file

In this case (booting with a key file), the error was different:

  Volume group "vg-ssd" not found
  Cannot process volume group vg-ssd
  Volume group "vg-hdd" not found
  Cannot process volume group vg-hdd
  Volume group "vg-hdd" not found
  Cannot process volume group vg-hdd
  Volume group "vg-hdd" not found
  ...
  Cannot process volume group vg-hdd
  Volume group "vg-hdd" not found
  Cannot process volume group vg-hdd
  mdadm: error opening /dev/md?*: No such file or directory
  Cannot process volume group vg-hdd
  Volume group "vg-hdd" not found

then the boot process drops to initramfs shell. Exploring the filesystem
at this stage, I didn't find the key file.

best regards,
Luc