What's going on with dm-crypt?!

[Celejar <celejar@gmail.com>]

Hi,

I have / on a luks volume, mounted with dm-crypt (automatically,
via /etc/fstab - /etc/crypttab). As recently as kernel 4.18.0-3,
everything was normal. With 4.19.0-1-amd64, the volume mounts, and the
system seems basically functional - but /dev/mapper is empty besides for
'control'!

~# ls -al /dev/mapper/
total 0
drwxr-xr-x  2 root root      60 Dec 23 23:32 .
drwxr-xr-x 18 root root    3340 Dec 23 23:32 ..
crw-------  1 root root 10, 236 Dec 23 23:32 control

Despite the fact that 'mount' shows that the dm-crypt mount is present:

~# mount | grep sda
/dev/mapper/sda2_crypt on / type ext4 (rw,relatime,errors=remount-ro)
/dev/sda1 on /boot type ext4 (rw,relatime)

~#

This situation causes update-initramfs to fail:

~# update-initramfs -u
update-initramfs: Generating /boot/initrd.img-4.19.0-1-amd64
mkinitramfs: failed to determine device for /
mkinitramfs: workaround is MODULES=most, check:
grep -r MODULES /etc/initramfs-tools

Error please report bug on initramfs-tools
Include the output of 'mount' and 'cat /proc/mounts'
update-initramfs: failed for /boot/initrd.img-4.19.0-1-amd64 with 1.

~#

Which is causing things like updating kernels to fail ...

What on earth is going on here?

Celejar