Comment 3 for bug 1832859

This is reported for issues with suspend and the example of /var/lib/libvirt/qemu/save.
But IMHO this would be true for the more common case of guest shutdown (the default) and /var being on an extra partition while the default image paths are under /var.
I know this would not be an immediate crash, since the running guests would block the unmount as long as needed, but having that more explicitly ordered might be good for that as well.