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Aquarius Power
Asked: 2014-08-01 22:06:48 +0800 CST

how to track a crash when changing from X :1 to X :0?

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I need to track on 14.04 a crash that often happens here:

I open a new X at :1 (that sometimes goes to ctrl+alt+f8 others to f9).
But when I try to go back to X :0 with ctrl+alt+f7, it crashes about 30% of the time...

The crash happens in a way that the login screen shows up again.

I looked at /var/log/apport.log and found this:

ERROR: apport (pid 769726) Fri Aug  1 00:47:56 2014: called for pid 1457, signal 6, core limit 18446744073709551615
ERROR: apport (pid 769726) Fri Aug  1 00:47:56 2014: ignoring implausibly big core limit, treating as unlimited
ERROR: apport (pid 769726) Fri Aug  1 00:47:56 2014: executable: /usr/bin/Xorg (command line "/usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch")
ERROR: apport (pid 769726) Fri Aug  1 00:47:56 2014: is_closing_session(): no DBUS_SESSION_BUS_ADDRESS in environment
ERROR: apport (pid 769726) Fri Aug  1 00:47:56 2014: apport: report /var/crash/_usr_bin_Xorg.0.crash already exists and unseen, doing nothing to avoid disk usage DoS

I think the answer can be a generic crash tracking information about: Xorg, xscreensaver, cpufreq and other apps that could potentially cause a crash in such virtual terminal changing situation. May be also applications related to OpenGL like Unity.

I just ensured no xscreensaver opengl hacks were running, just maze; and a crash happened again.

I lock the screen with xscreensaver, but after some time the unity default screenlocker kicks in also, so I have to login two times.

Useful News:
The crash seems clearly related to Unity 3D ignoring the presence of another VT?
I saw clearly that Unity HUD gets messed like "its 3D textures" get memory corrupted?
There is this script that check and ask to replace compiz with metacity --replace.
Since I begin using it, I have not had a single crash; unfortunately, when coming back to X:0 I have to compiz --replace (the script is ready to do that also).
This other script (that opens a new X session) also does these checks/give these options.

xorg

1 Answers

  1. This has been going on since upgrading to XUbuntu 16.04 (no Unity, 3D or otherwise), 64 bit. Here's a fresh apport.log:

    ERROR: apport (pid 5067) Sun Sep  4 12:10:39 2016: called for pid 2649, signal 6, core limit 18446744073709551615

ERROR: apport (pid 5067) Sun Sep  4 12:10:39 2016: ignoring implausibly big core limit, treating as unlimited

ERROR: apport (pid 5067) Sun Sep  4 12:10:39 2016: executable: /usr/lib/xorg/Xorg (command line "/usr/lib/xorg/Xorg -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch")

ERROR: apport (pid 5067) Sun Sep  4 12:10:39 2016: is_closing_session(): no DBUS_SESSION_BUS_ADDRESS in environment

ERROR: apport (pid 5067) Sun Sep  4 12:10:39 2016: apport: report /var/crash/_usr_lib_xorg_Xorg.0.crash already exists and unseen, doing nothing to avoid disk usage DoS

    (I allow the system to send reports on the problem.)

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