Comment 22 for bug 1555760

2c - just hit this myself on xenail s390x with a soaking openstack-on-lxd installation.

masking proc-sys-fs-binfmt_misc.automount seemed to be a bad idea... systemd is in a bad state..

ubuntu@zs93kvi:~$ systemctl -a | grep binfmt
  proc-sys-fs-binfmt_misc.automount loaded active running Arbitrary Executable File Formats File System Automount Point
  proc-sys-fs-binfmt_misc.mount loaded inactive dead Arbitrary Executable File Formats File System
  systemd-binfmt.service loaded inactive dead Set Up Additional Binary Formats
ubuntu@zs93kvi:~$ sudo systemctl mask proc-sys-fs-binfmt_misc.automount
Created symlink from /etc/systemd/system/proc-sys-fs-binfmt_misc.automount to /dev/null.
ubuntu@zs93kvi:~$
Broadcast message from systemd-journald@zs93kvi (Fri 2017-05-05 10:25:46 EDT):

systemd[1]: Caught <ABRT>, dumped core as pid 23484.

Broadcast message from systemd-journald@zs93kvi (Fri 2017-05-05 10:25:46 EDT):

systemd[1]: Freezing execution.