Comment 63 for bug 1755863

xenial (note, the test case repro is slightly different for x, the systemctl stop fails instead of the start):

root@lp1755863-x:~# dpkg -l | grep systemd0
ii libsystemd0:amd64 229-4ubuntu21.16 amd64 systemd utility library
root@lp1755863-x:~# mount | grep test
tmpfs on /test type tmpfs (rw,nosuid,nodev,relatime)
root@lp1755863-x:~# systemctl mask media.mount
Created symlink from /etc/systemd/system/media.mount to /dev/null.
root@lp1755863-x:~# systemctl stop test.mount
Job for test.mount failed. See "systemctl status test.mount" and "journalctl -xe" for details.

root@lp1755863-x:~# dpkg -l | grep systemd0
ii libsystemd0:amd64 229-4ubuntu21.17 amd64 systemd utility library
root@lp1755863-x:~# mount | grep test
tmpfs on /test type tmpfs (rw,nosuid,nodev,relatime)
root@lp1755863-x:~# systemctl mask media.mount
Created symlink from /etc/systemd/system/media.mount to /dev/null.
root@lp1755863-x:~# systemctl stop test.mount
root@lp1755863-x:~# mount | grep test