Those of you who are seeing similar problems; could you try to get a core dump and a full stack trace?
Here's how I managed to do it: 1. Prevent X from trapping SIGSEGV by putting the following in /usr/share/X11/xorg.conf.d/00-no-trap-signals.conf: Section "ServerFlags" Option "NoTrapSignals" "true" EndSection 2. Tell X to dump core by adding the following to the [SeatDefaults] section of /etc/lightdm.conf: xserver-command=X -core 3. Make sure the X is allowed to dump core: - log out from your session - switch to another VT (ctrl-alt-f1) - sudo stop lightdm - ulimit -c unlimited - sudo lightdm 4. Check that the changes kicked in: $ ps -fp $(pidof X) UID PID PPID C STIME TTY TIME CMD root 16043 6885 1 08:44 tty7 00:01:34 /usr/bin/X -core :7 -auth /var/run/lightdm/root/:7 -nolisten tcp vt7 -novtswitch $ cat /proc/$(pidof X)/limits | grep core Max core file size unlimited unlimited bytes $ 5. Switch back to VT7, log in and wait for X to crash again. 6. To get meaningful stacktraces, you'll want debug symbols installed for X and friends (adjust for different video drivers): sudo apt-get install libc6-dbg xserver-xorg-core-dbg xserver-xorg-video-intel-dbg 7. If/when X crashes, check for /etc/X11/core. If it exists, copy it to your home dir and run: gdb /usr/bin/Xorg core 8. In gdb, say "bt full" to get a stacktrace. -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/1026777 Title: Xorg segfault: kicks out to login screen To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1026777/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp