Guest accounts may not be removed properly on system reboot

[Laércio de Sousa]

I've noticed that guest accounts may not be cleanly removed from my system if I stop lightdm directly (e.g. on reboot without logging out first). This may lead to a situation where guest login fails due to lack of available GIDs (which shorten more quickly than UIDs).

A possible workaround for this problem is the addition of a pre-start (or post-stop) stanza to flush all remaining guest accounts. At least for systemd, the ExecStartPre option is preferable, because ExecStopPost may not be run if system is rebooted/halted with "systemctl --force".

This problem may affect Precise/Trusty, too.

[Robert Ancell (robert-ancell)]

Related to bug 1259562?

[Laércio de Sousa (lbssousa)]

Not sure. I'm running these tests in Debian, which doesn't install AccountsService by default. There are no leftovers in my filesystem, but there may be letfover entries in /etc/passwd and /etc/group if not logging out guest before stopping lightdm service.