Comment 4 for bug 1892124

One interesting finding is that kernel06 is not failing with this issue. Command `dpkg -l | grep zfs` returns nothing.

On other s390x instances,
The zfs module can be removed by stopping the zed service first:
ubuntu@kernel04:~$ lsmod | grep zfs
zfs 3936256 6
zunicode 335872 1 zfs
zlua 192512 1 zfs
zcommon 114688 1 zfs
znvpair 110592 2 zfs,zcommon
zavl 16384 1 zfs
icp 299008 1 zfs
spl 159744 5 zfs,icp,znvpair,zcommon,zavl
ubuntu@kernel04:~$ dpkg -l |grep zfs
ii libzfs2linux 0.8.3-1ubuntu12.10 s390x OpenZFS filesystem library for Linux
ii zfs-zed 0.8.3-1ubuntu12.10 s390x OpenZFS Event Daemon
ii zfsutils-linux 0.8.3-1ubuntu12.10 s390x command-line tools to manage OpenZFS filesystems
ubuntu@kernel04:~$ sudo systemctl stop zed
ubuntu@kernel04:~$ lsmod | grep zfs
zfs 3936256 0
zunicode 335872 1 zfs
zlua 192512 1 zfs
zcommon 114688 1 zfs
znvpair 110592 2 zfs,zcommon
zavl 16384 1 zfs
icp 299008 1 zfs
spl 159744 5 zfs,icp,znvpair,zcommon,zavl
ubuntu@kernel04:~$
ubuntu@kernel04:~$ sudo modprobe -r zfs

Dig deeper, it shows that the zed (zfs-zed) comes with the zfsutils-linux package which was installed by zfs related tests in our test suite. We should add a remove code to remove that package in the end of the test.