Comment 59 for bug 976124

> First message in second seat greeter log file is logged after less
> than 1 second when I log in in first seat. At this moment greeter
> starts eating cpu.

Please attach a debugger and get a stack trace when this happens.

>> Does the greeter crash, exit, or move to the background?
>
> Greeter crashes.

Please get a stack trace, either by looking at the core file or by
attaching a debugger before it crashes.

> * Tried several times restart pc, but unity-greeter didn't start on
> my seat. Seat with autologin still worked fine. Than I edited
> /var/lib/lightdm/.cache/unity-greeter/seat0-state and changed
> last-user back to what I use on my first seat.

unity-greeter runs some code whenever a user is selected (including
selecting the last logged-in user when unity-greeter starts up). For
example, it does some PAM stuff to see if a password is required for
the user that was selected. Something in this code must be crashing.

In addition to the stack traces, please collect the following
information (before logging in via unity-greeter, so use Ctrl-Alt-F1
to log in via a VT or ssh into the machine):

  * unity-greeter environment variables:

    for pid in $(pidof unity-greeter); do
        printf '\n%s\n---------\n' "pid $pid"
        sudo cat /proc/$pid/environ | tr '\0' '\n'
    done >>unity-greeter-environ.txt

  * unity-greeter session processes: For each session listed in
    'loginctl list-sessions', do:

    loginctl --full --no-pager session-status $session_name >>sessions.txt