For some odd reason, a bunch of services on Eru just... stopped responding. I logged in to the virtual console, and saw that journald complained about running out of disk space (it shouldn't save anything to disk). Logged in there, restarted a bunch of things, ssh still stuck.
So I ended up rebooting.
No PHP involved.
51% of
/(tmpfs) was free when I logged in, and there was plenty of space elsewhere, so I assume that journald failing to persist stuff made it drop it instead, and thereby fixing the problem.I suspect that it was journald that held things up, though. Next time (if there's a next time), I'll try restarting that too.