abnormal logout debugging

Question

I am getting some abnormal behaviour lately from my Ubuntu 14.04.4 LTS Desktop machine. With no apparent reason or failure, all program close and I get logged out. I have also noticed lately a lot of WebGL chrashes in my Chromium and Chrome. I have no idea if is some hardware or software failure, although the fact that is not a full restart, but only a logout makes me think is a software issue.

I was looking at /var/log/syslog and I have this logs since last restart which does not point me to a specific error:

Apr  1 09:49:40 v24 NetworkManager[910]: <warn> error requesting auth for org.freedesktop.NetworkManager.wifi.share.open: (3) GDBus.Error:org.freedesktop.DBus.Error.NameHasNoOwner: GDBus.Error:org.freedesktop.DBus.Error.NameHasNoOwner: Could not get UID of name ':1.439': no such name
Apr  1 09:49:40 v24 colord: device removed: xrandr-Goldstar Company Ltd-E2750-010MAAKDF872
Apr  1 09:49:40 v24 colord: Profile removed: icc-a8ff8ebef3b548f46e2eddd5c6ba1217
Apr  1 09:49:42 v24 dbus[565]: [system] Activating service name='org.freedesktop.systemd1' (using servicehelper)
Apr  1 09:49:42 v24 dbus[565]: [system] Successfully activated service 'org.freedesktop.systemd1'
Apr  1 09:49:42 v24 rtkit-daemon[1419]: Successfully made thread 7851 of process 7851 (n/a) owned by '1000' high priority at nice level -11.
Apr  1 09:49:42 v24 rtkit-daemon[1419]: Supervising 6 threads of 2 processes of 2 users.
Apr  1 09:49:42 v24 pulseaudio[7851]: [pulseaudio] pid.c: Stale PID file, overwriting.
Apr  1 09:49:42 v24 gnome-session[7701]: WARNING: Could not parse desktop file fluxgui.desktop or it references a not found TryExec binary
Apr  1 09:49:42 v24 rtkit-daemon[1419]: Successfully made thread 7865 of process 7851 (n/a) owned by '1000' RT at priority 5.
Apr  1 09:49:42 v24 rtkit-daemon[1419]: Supervising 7 threads of 2 processes of 2 users.
Apr  1 09:49:42 v24 rtkit-daemon[1419]: Successfully made thread 7867 of process 7851 (n/a) owned by '1000' RT at priority 5.
Apr  1 09:49:42 v24 rtkit-daemon[1419]: Supervising 8 threads of 2 processes of 2 users.
Apr  1 09:49:43 v24 rtkit-daemon[1419]: Successfully made thread 7904 of process 7851 (n/a) owned by '1000' RT at priority 5.
Apr  1 09:49:43 v24 rtkit-daemon[1419]: Supervising 9 threads of 2 processes of 2 users.
Apr  1 09:49:43 v24 rtkit-daemon[1419]: Successfully made thread 7908 of process 7851 (n/a) owned by '1000' RT at priority 5.
Apr  1 09:49:43 v24 rtkit-daemon[1419]: Supervising 10 threads of 2 processes of 2 users.
Apr  1 09:49:43 v24 rtkit-daemon[1419]: Successfully made thread 7913 of process 7913 (n/a) owned by '1000' high priority at nice level -11.
Apr  1 09:49:43 v24 rtkit-daemon[1419]: Supervising 11 threads of 3 processes of 2 users.
Apr  1 09:49:43 v24 pulseaudio[7913]: [pulseaudio] pid.c: Daemon already running.
Apr  1 09:49:43 v24 rtkit-daemon[1419]: Successfully made thread 7915 of process 7915 (n/a) owned by '1000' high priority at nice level -11.
Apr  1 09:49:43 v24 rtkit-daemon[1419]: Supervising 12 threads of 4 processes of 2 users.
Apr  1 09:49:43 v24 pulseaudio[7915]: [pulseaudio] pid.c: Daemon already running.
Apr  1 09:49:43 v24 dbus[565]: [system] Activating service name='org.freedesktop.locale1' (using servicehelper)
Apr  1 09:49:43 v24 dbus[565]: [system] Successfully activated service 'org.freedesktop.locale1'
Apr  1 09:49:43 v24 colord: Device added: xrandr-Goldstar Company Ltd-E2750-010MAAKDF872
Apr  1 09:49:43 v24 colord: Automatic metadata add icc-6b6960b48cebea3c9fcce46bc55028fb to xrandr-Goldstar Company Ltd-E2750-010MAAKDF872
Apr  1 09:49:43 v24 colord: Profile added: icc-6b6960b48cebea3c9fcce46bc55028fb

I am looking for suggestions on how to start investigating what is going on.

UPDATE

$ last -f /var/log/wtmp
    valugi   pts/4        :0               Thu Apr  7 15:22   still logged in   
    valugi   pts/1        :0               Thu Apr  7 13:19   still logged in   
    valugi   pts/17       :0               Thu Apr  7 13:03 - 13:04  (00:00)    
    valugi   :0           :0               Thu Apr  7 13:03   still logged in   
    reboot   system boot  3.13.0-85-generi Thu Apr  7 13:03 - 15:24  (02:21)    
    valugi   pts/10       :0               Thu Apr  7 12:47 - 13:01  (00:13)    
    valugi   pts/3        :0               Thu Apr  7 12:45 - 12:52  (00:06)    
    valugi   :0           :0               Thu Apr  7 12:23 - down   (00:37)    
    valugi   pts/11       :0               Thu Apr  7 11:38 - 12:23  (00:44)    
    valugi   pts/3        :0               Tue Apr  5 07:01 - 12:23 (2+05:22)   
    valugi   pts/10       :0               Mon Apr  4 17:21 - 12:23 (2+19:01)   
    valugi   :0           :0               Mon Apr  4 17:21 - 12:23 (2+19:01)   
    valugi   pts/6        :0               Mon Apr  4 10:26 - 17:20  (06:53)    
    valugi   pts/15       :0               Mon Apr  4 00:09 - 17:20  (17:11)    
    valugi   pts/6        :0               Sun Apr  3 22:53 - 23:07  (00:13)    
    valugi   pts/3        :0               Sun Apr  3 22:08 - 17:20  (19:12)    
    valugi   :0           :0               Sun Apr  3 20:35 - 17:20  (20:45)    
    valugi   pts/9        :0               Fri Apr  1 09:49 - 20:35 (2+10:45)   
    valugi   :0           :0               Fri Apr  1 09:49 - 20:35 (2+10:45) 

Answer 1

You may need to look at some other logs for a cause

After getting logged out check

tail /var/log/Xorg*log.old

To see if there has been an X-Server crash due to bad GPU drivers/hardware error etc, if the x-server crashes the default behavior would be to restart it giving you the impression that you were logged out

You may also check the display manager log (after the logout occurs) /var/log/lightdm/lightdm.log.old

If no errors found there when your desktop logs in fire up a terminal and do

dbus-monitor > ~/dbuslog.txt

After a crash you can check dbuslog.txt to see if any logout signal was sent via dbus

Answer 2

Is it an AMD machine? I had similar problems with Lenovo AMD A8 6410 machine. In my case the graphics driver was the cause.