zpool freezes importing older ZFS pool, blocks shotdown and system does not boot

[Nikola M]

After fresh install of xubuntu 18.04 LTS 64-bit,
and the installation of zfs-dkms I tried to do 'zpool import' on an older ZFS pool, consisting of on partition on the separate PATA HDD.

After issuing 'sudo zpool import <poolname>' , command freezes (as to zfs commands).
System then fails to shutdown properly and seems locked and needs hard reboot (actually it waits up to half an hour to shutdown).
After restarting, system displays Xubuntu splash screen and does not boot anymore (it actually resets itself if given again half an hour or so).

When getting to rescue options, by pressing SHIFT key on keyboard and going to shell and remounting / read-write, I could do removing of ZFS Ubuntu packages and after that system could boot.

Usefull message I got when trying to continue booting in shell was:
"[ 40.811792] VERIFY3(0 == remove_reference(hdr, ((void *)0), tag)) failed (0 = 0)
[ 40.811856] PANIC at arc.c:3084:arc_buf_destroy()"

So it points to some ZFS bug with ARC.

Previously, I was able to (unlike with 17.10) upgrade from 17.10 to 18.04 and to import and use a newer ZFS pool.
But this bug is about fresh 18.04 install and an older ZFS pool. (zpool import says pool can be upgraded)

[Colin Ian King (colin-king)]

The zfs-dkms package should be removed as the kernel includes the ZFS + SPL drivers. You just need to install zfsutils-linux. Please try the following:

sudo apt-get purge zfs-dkms
sudo apt-get install --reinstall zfsutils-linux

[Nikola M (nikolam)]

I get the same results when purging zfs-dkms and --reinstall zfsutils-linux .
System is unbootable (resets after a long time) and shutdown can't be done (also takes very much time).
All happens after 'zpool import <olderpoolname>'

[Colin Ian King (colin-king)]

This looks very similar to the following ZFS bug report

https://github.com/zfsonlinux/zfs/issues/6881

It may indicate you have data corruption and degraded pool. It's hard to tell any further. Have you been able to resolve this issue?

[Colin Ian King (colin-king)]

This bug has not been updated with further information requested in question 4 for over a year. Marking as Won't Fix.