Comment 7 for bug 1708051

xnox and I debugged this together, and it seems like the upload of 234 in Debian switched to Meson, and there was a bug introduced here where KillUserProcesses was set back to `yes' instead of `no' as it's meant to be. To reboot the machine, autopkgtest runs `sh -c (sleep 3; reboot) &' over SSH. When we background this and then end the SSH connection - and logind session - systemd kills the sleep and the reboot is never run, so we see a system that has come up but never gone down.

I found this by entering a machine in the bad state and looking at the journal. In future I suggest that systemd's autopkgtests output the journal to their log so that this would be debuggable without admin access next time.