There is an issue around currently for Red Hat based systems, Oracle Linux here, in version
219-30.0.1, having a
reboot seemingly hang on a failed swap unit (deallocation). A lot of posts on the net discuss the issue, After switching to Ubuntu 15.04 laptop won’t shutdown suggested the w/a, doing a
swapon bounce in advance, that worked for me, referencing reboot hangs at ‘Reached target Shutdown’. Systemd: Hangs indefinitely on >90% of reboot attempts comprises in in-depth analysis.
I’m not shure, though, whether tmp.mount.hm4: After swap.target is releated, really, because the implemented change is already present on my systems (
systemd‘s). I’m much more tending to suspect widespread storage fragmentation on the swap area to cause the relatively long term swap off run-times. In addition, I almost only experienced the issue for systems that have been up for a longer number of days, say from 90 days onwards.