I have posted this issue on ServerFault[1] and AskUbuntu[2] but got closed or no answer so far (~18 hours ago)
Here are the facts:
* I ran some stress-tests last night.
* I forgot to reset the logs to minimal.
* When I got this morning, I saw that hard drive is full /dev/sda1.
* Cleaned up the large file (350GB).
* I experienced the machine being a bit slowlier than usual.
* I rebooted the machine.
Since then, when I try to login, the computer shows as if it let me in, and yet, prompt for login again.If I provide the wrong password on purpose, it shows the usual error. When I provide the right one, it is like an infinite loop.
When I hit Ctrl+Alt+F1 and login at tty1, for instance, all works fine.
From tty1, I tried to setup auto-login as follows:
sudo vim /etc/lightdm/lightdm.conf
autologin-user=<username>
autologin-user-timeout=0
Yet, it doesn't perform the auto login for some reason.I also tried `startx` from tt1, re-installed `gdm`, `lightdm` but with no help. All I see is an error at /var/log/lightdm/lightdm.log that the process gdm-greeter get killed
[1] http://askubuntu.com/questions/256344/cannot-login-to-my-machine-using-the-right-password [2] http://serverfault.com/questions/479126/cannot-login-to-my-machine-using-the-right-password