xorg crashes after switching from tty7 -> tty1 -> tty7

[Steve Beattie]

Binary package hint: xorg

xorg crashes after switching vts from tty7 -> tty1 -> tty7. apport does not catch anything, though the log shows a backtrace. This only manifests after X has been running for a while, newly started X does not crash in this way.

Backtrace:
0: /usr/bin/X (xorg_backtrace+0x28) [0x4a3248]
1: /usr/bin/X (0x400000+0x655ad) [0x4655ad]
2: /lib/libpthread.so.0 (0x7ffdbe135000+0xf8f0) [0x7ffdbe1448f0]
3: /usr/bin/X (0x400000+0x13adb6) [0x53adb6]
4: /usr/bin/X (0x400000+0x13d32d) [0x53d32d]
5: /usr/bin/X (0x400000+0x13d5f2) [0x53d5f2]
6: /usr/bin/X (xf86Wakeup+0x43f) [0x4702df]
7: /usr/bin/X (WakeupHandler+0x4b) [0x435f2b]
8: /usr/bin/X (WaitForSomething+0x1d7) [0x45f997]
9: /usr/bin/X (0x400000+0x30952) [0x430952]
10: /usr/bin/X (0x400000+0x261aa) [0x4261aa]
11: /lib/libc.so.6 (__libc_start_main+0xfd) [0x7ffdbce2dc4d]
12: /usr/bin/X (0x400000+0x25d59) [0x425d59]
Segmentation fault at address 0x14

Caught signal 11 (Segmentation fault). Server aborting

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: xorg 1:7.5+3ubuntu1
ProcVersionSignature: Ubuntu 2.6.32-19.28-generic 2.6.32.10+drm33.1
Uname: Linux 2.6.32-19-generic x86_64
Architecture: amd64
CheckboxSubmission: 9c15077a0ca11678d04e060687c26674
CheckboxSystem: 5dc75472945f57d094b84e90feb97396
Date: Thu Apr 8 10:38:35 2010
MachineType: LENOVO 8897CTO
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-19-generic root=UUID=ab7c1e48-2b72-48b9-8a34-e17be5fea3b6 ro quiet splash rootflags=data=ordered
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: xorg
dmi.bios.date: 05/11/2009
dmi.bios.vendor: LENOVO
dmi.bios.version: 7LETC6WW (2.26 )
dmi.board.name: 8897CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr7LETC6WW(2.26):bd05/11/2009:svnLENOVO:pn8897CTO:pvrThinkPadT61:rvnLENOVO:rn8897CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 8897CTO
dmi.product.version: ThinkPad T61
dmi.sys.vendor: LENOVO
system:
 distro: Ubuntu
 codename: lucid
 architecture: x86_64
 kernel: 2.6.32-19-generic

[Bryce Harrington (bryce)]

Are you able to reproduce this issue easily? If so, please collect a full backtrace - see http://wiki.ubuntu.com/X/Backtracing for directions. If not, could you describe the conditions under which the crash tends to occur?

[Steve Beattie (sbeattie)]

Sorry, no, I'm not able to reproduce it on demand. It has occurred at least a couple of times since I upgraded to Lucid, after running for at least a couple of weeks. Typically the trigger has been milestone iso testing, where due to some quirks I end up using multiple virtualization tools with different shortcuts for switching to a tty on the guest, and I end up accidentally switching to tty1 on my laptop. It's the switch back when X crashes (as near as I can tell). That said, virtualbox is the only virtualization tool running locally on the laptop.

[Heikki Keränen (heikki-a-keranen)]

I'am able to reproduce this consistently.

Configuration:
HP laptop nx7400, Intel GMA 950.
HP LP2475w 1920x1200 external display connected to the laptop via VGA1
no xorg.conf, default desktop effects enabled
In my account I have enabled the external display (VGA1) and disabled the laptop display (LVDS1) from graphical preferences dialog. Laptop lid is open all the time. Here is the xrandr output:
---
~$ xrandr
Screen 0: minimum 320 x 200, current 1920 x 1200, maximum 4096 x 4096
VGA1 connected 1920x1200+0+0 (normal left inverted right x axis y axis) 546mm x 352mm
1920x1200 60.0*+ 59.9
--clip---
LVDS1 connected (normal left inverted right x axis y axis)
1680x1050 60.1 +
--clip--
TV1 disconnected (normal left inverted right x axis y axis)
----

Steps to reproduce:
1. Reboot
2. Type in Luks password (I have encrypted root) (both laptop and external are displaying the same image)
3. Log in (again both laptop and external displaying the same image)
After login only external VGA1 is displaying image.
4. Press: Ctrl+Alt+F1, result: both laptop and external display are displaying the same image
5. Press: Ctrl+Alt+F7,
EXPECTED result: back to the logged in desktop,
ACTUAL result: login screen displaying that nobody is logged in anymore
6. Log in. Now the xorg session is at VT8 and the bug cannot be reproduced anymore without reboot.

[Heikki Keränen (heikki-a-keranen)]

I'am also able to reproduce this with my another laptop:
Acer Aspire One, also having Intel GMA 950 and running Lucid.

Same steps as in my previous comment above work. I couln't reproduce the bug without external display.

[Heikki Keränen (heikki-a-keranen)]

Also normal user switching from GUI triggers the bug:

Preparations:
===========
1. Plug in external monitor to your laptop (bug does not trigger with single display setup)
2. Adjust your display settings (from the preferences menu) so that the image is displayed only on the external monitor OR on the laptop screen, but NOT on both
3. Do not close your laptop lid, closing it prevents the bug from triggering (since login screen is not presented on multiple monitors)

Steps to reproduce:
================
1. Reboot (or shut down and power on)
- at this point the login screen should be displayed on both monitors
2. Log in
- at this point only external OR only interal monitor should be displaying image
3. from "Indicator Applet Session" -> Switch From account...
- login screen is presented, your account should be marked with a green checkmark and "logged in" text
- this screen should be displayed on both monitors
4. Click your account and enter password
EXPECTED RESULT: you get back to your already active desktop session
ACTUAL RESULT: X crashes, new login screen is presented displaying that nobody is logged in

- to reproduce again, you must reboot

So no using keyboard is needed to switch between VT:s. Bug triggers in very ordinary multiuser situations.

Tested with two different up to date, clean installed, encrypted Lucid laptops having Intel GMA 950 display adapter.

[zorgoth (freepskov)]

I also am experiencing this bug with an encrypted Lucid desktop with an ATI Radeon HD 2400. It happens invariably when logged out and occasionally when logged in. If you run "sudo killall Xorg" to restore X, then you will get a new GNOME session but switching to a virtual console will then invariably crash.

[zorgoth (freepskov)]

Interestingly, simply pressing Ctrl-Alt-F7 in tty7 (or whatever it's called) GNOME will also produce this bug.

[Launchpad Janitor (janitor)]

[Expired for xorg-server (Ubuntu) because there has been no activity for 60 days.]