unity-panel-service crashed with SIGSEGV in panel_indicator_entry_accessible_get_n_children()

[Thomas Bechtold]

Unity is gone. No launcher, no menues.

i did:

- supend laptop (laptop was attached to docking station)
- power on laoptop
- press docking station button to detach laptop
- detach laptop

Now i started ubuntu --advanced-debug from tty1. Attached is the output of gdb. I can reproduce the issue. i switch to tty1, start the program in gdb with "run" and the all seems to work. When i switch bach to X (ctrl+alt+7), my program windows disappear and come back. then back to tty1 i have the crash output.

ProblemType: Crash
DistroRelease: Ubuntu 12.10
Package: unity-services 6.0.0-0ubuntu1
ProcVersionSignature: Ubuntu 3.5.0-4.4-generic 3.5.0-rc6
Uname: Linux 3.5.0-4-generic i686
ApportVersion: 2.3-0ubuntu4
Architecture: i386
CrashCounter: 1
Date: Sat Jul 14 16:05:26 2012
ExecutablePath: /usr/lib/unity/unity-panel-service
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423.2)
ProcCmdline: /usr/lib/unity/unity-panel-service
SegvAnalysis: Failure: Unknown offset literal: [edx]
Signal: 11
SourcePackage: unity
StacktraceTop:
 ?? ()
 atk_object_get_n_accessible_children () from /usr/lib/i386-linux-gnu/libatk-1.0.so.0
 ?? () from /usr/lib/i386-linux-gnu/libatk-bridge-2.0.so.0
 g_idle_dispatch (source=source@entry=0x9822d68, callback=0xb69a6e40, user_data=0x8e5a2e0) at /build/buildd/glib2.0-2.33.3/./glib/gmain.c:4657
 g_main_dispatch (context=0x8cdb668) at /build/buildd/glib2.0-2.33.3/./glib/gmain.c:2539
Title: unity-panel-service crashed with SIGSEGV in atk_object_get_n_accessible_children()
UpgradeStatus: Upgraded to quantal on 2012-06-23 (21 days ago)
UserGroups: adm cdrom dip kvm libvirtd lpadmin plugdev sambashare sudo vboxusers

[Thomas Bechtold (toabctl)]

i tried a "restart lightdm" after that (without a reboot) and now all is flickering. there are large black/white boxes on the screen. but that changes with every mouse movement.

[Apport retracing service (apport)]

StacktraceTop:
 panel_indicator_entry_accessible_get_n_children (accessible=0x8eb21d8) at /build/buildd/unity-6.0.0/services/panel-indicator-entry-accessible.c:256
 atk_object_get_n_accessible_children () from /tmp/tmp2qypaM/usr/lib/i386-linux-gnu/libatk-1.0.so.0
 append_children (traversal=0x8d7e990, accessible=0x8eb21d8) at accessible-cache.c:235
 add_pending_items (data=data@entry=0x8e5a2e0) at accessible-cache.c:291
 g_idle_dispatch (source=source@entry=0x9822d68, callback=0xb69a6e40 <add_pending_items>, user_data=0x8e5a2e0) at /build/buildd/glib2.0-2.33.3/./glib/gmain.c:4657

[Thomas Bechtold (toabctl)]

Another gdb output after the lightdm restart.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Stephen M. Webb (bregma)]

The GDB retrace of Unity indicates a crash in the 3D video driver, probably due to poor power management capabilities in the driver itself. That, and the symptoms described in the Bug Description, are not related to unity-panel-service which is a separate process from unity.

There is still a crash in unity-panel-service to be investigated here.

[Sebastien Bacher (seb128)]

seems a bit similar to bug #1040660 or to the bug fixed with: http://bazaar.launchpad.net/~unity-team/unity/trunk/revision/2775