Creating initramfs fails since initramfs-tools* version 0.137

Hi all,

this is possibly related to [1] but I'm unsure about it.

[1]: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=950254

When upgrading my OS installation of Debian unstable on my first c8000 a
few minutes ago, a new kernel was installed and hence a new initramfs
was to be created. Unfortunately that last step failed. I am running the
c8000 from an NFS root FS and even removing and purging kernels and
initramfs-tools* and reinstalling the current kernel (which again pulls
in initramfs-tools*) did not make it work:

```
root@c8000:/# apt install linux-image-parisc64
[...]
Setting up initramfs-tools-core (0.137) ...
Setting up initramfs-tools (0.137) ...
update-initramfs: deferring update (trigger activated)
Setting up linux-image-5.6.0-2-parisc64 (5.6.14-2) ...
I: /vmlinux.old is now a symlink to boot/vmlinuz-5.6.0-2-parisc64
I: /initrd.img.old is now a symlink to boot/initrd.img-5.6.0-2-parisc64
I: /vmlinux is now a symlink to boot/vmlinuz-5.6.0-2-parisc64
I: /initrd.img is now a symlink to boot/initrd.img-5.6.0-2-parisc64
/etc/kernel/postinst.d/initramfs-tools:
update-initramfs: Generating /boot/initrd.img-5.6.0-2-parisc64
E: /usr/share/initramfs-tools/hooks/udev failed with return 1.
update-initramfs: failed for /boot/initrd.img-5.6.0-2-parisc64 with 1.
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
dpkg: error processing package linux-image-5.6.0-2-parisc64 (--configure):
  installed linux-image-5.6.0-2-parisc64 package post-installation
script subprocess returned error exit status 1
dpkg: dependency problems prevent configuration of linux-image-parisc64:
  linux-image-parisc64 depends on linux-image-5.6.0-2-parisc64 (=
5.6.14-2); however:
   Package linux-image-5.6.0-2-parisc64 is not configured yet.

dpkg: error processing package linux-image-parisc64 (--configure):
  dependency problems - leaving unconfigured
Processing triggers for systemd (245.6-1) ...
Processing triggers for mime-support (3.64) ...
Processing triggers for libc-bin (2.30-8) ...
Processing triggers for initramfs-tools (0.137) ...
Errors were encountered while processing:
  linux-image-5.6.0-2-parisc64
  linux-image-parisc64
E: Sub-process /usr/bin/dpkg returned an error code (1)
```

Even when running `update-initramfs` in verbose mode, I can't get any
additional information for the run of the udev hook with version 0.137.
Any suggestions how to further debug this issue?

Downgrading initramfs-tools* to version 0.136 seems to solve the issue
for me:

```
root@c8000:/# dpkg -i initramfs-tools_0.136_all.deb
initramfs-tools-core_0.136_all.deb
dpkg: warning: downgrading initramfs-tools from 0.137 to 0.136
(Reading database ... 27443 files and directories currently installed.)
Preparing to unpack initramfs-tools_0.136_all.deb ...
Unpacking initramfs-tools (0.136) over (0.137) ...
dpkg: warning: downgrading initramfs-tools-core from 0.137 to 0.136
Preparing to unpack initramfs-tools-core_0.136_all.deb ...
Unpacking initramfs-tools-core (0.136) over (0.137) ...
Setting up initramfs-tools-core (0.136) ...
Setting up initramfs-tools (0.136) ...
update-initramfs: deferring update (trigger activated)
Processing triggers for initramfs-tools (0.136) ...

root@c8000:/# dpkg --configure -a
Setting up linux-image-5.6.0-2-parisc64 (5.6.14-2) ...
/etc/kernel/postinst.d/initramfs-tools:
update-initramfs: Generating /boot/initrd.img-5.6.0-2-parisc64
Setting up linux-image-parisc64 (5.6.14-2) ...
```

BTW, the new kernel is not working for me and panics very early, but
this should maybe go to a different message.

Cheers,
Frank