Invalid password after long uptime

[Michael Parks]

After a 15.04 system has been running for a long time (more than 2-3 days), and the system has locked the screen automatically during inactivity, attempting to unlock the screen will result in an "invalid password" message at the lock screen, despite using the correct password.

The only fix I've found is to jump to a TTY, log in there (which works), and do a "sudo service lightdm restart".

I've made no changes to my PAM configuration, nor do I have any packages installed which modify it.

Only other thing I've noticed is that normally, my screens go to sleep after the display is locked. Every time this problem presents itself, the displays have awoken at some point overnight.

No obvious errors in auth.log, xorg.log, or lightdm.log.

Using the proprietary NVIDIA drivers.

Unity Installed: 7.3.2+15.04.20150420-0ubuntu

[Andrea Azzarone (azzar1)]

Please make sure that when this happens the keyboard layout is correct.

[Michael Parks (tk-4)]

System layout is pc105/us, and this doesn't impact system behavior at any other time. Only the login screen, and only after days have passed.

[Michael Parks (tk-4)]

Is there a way I can gather information as to what Unity thinks its doing when that invalid password prompt comes up?

[Andrea Azzarone (azzar1)]

Well unity is just using PAM to check if the password is correct. You can try to reproduce the problem with gnome-screensaver. If it happens with g-s as well then it's not unity's fault.

[Michael Parks (tk-4)]

Just got it again, this time immediately after a screen lock. As usual, had to jump to a terminal, lightdm restart, and blow away my session.

No login failures counted in /var/log/faillog (faillog -u myuser shows 0).

That leads me to think it's not even communicating with PAM in this state....

I'll give the screensaver idea a try, at least. I think killing it off from a root shell on another TTY would be less destructive than having to wipe out my session :)

I can tell you that when it does get in this state, absolutely nothing will allow my user account to unlock the screen - so again, is there any kind of debug logging, tracing, etc I could enable?

[Launchpad Janitor (janitor)]

[Expired for unity (Ubuntu) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for Unity because there has been no activity for 60 days.]