compiz crashed with SIGSEGV in g_datalist_id_set_data_full()

[Robert Ancell]

Happened when I disconnected an external monitor. Only the background was visible, then the windows restacked and compiz restarted.

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: libnux-2.0-0 2.0.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.2.0-12.20-generic 3.2.2
Uname: Linux 3.2.0-12-generic x86_64
ApportVersion: 1.91-0ubuntu1
Architecture: amd64
CheckboxSubmission: e440e09ef58a53bccc45087674ba6b8e
CheckboxSystem: d00f84de8a555815fa1c4660280da308
CrashCounter: 1
Date: Mon Jan 30 11:06:10 2012
EcryptfsInUse: Yes
ExecutablePath: /usr/bin/compiz
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Beta amd64 (20110330)
ProcCmdline: compiz
SegvAnalysis:
 Segfault happened at: 0x7f006e938b55 <g_datalist_id_set_data_full+341>: mov 0x0(%r13),%esi
 PC (0x7f006e938b55) ok
 source "0x0(%r13)" (0xaaaaaaaaaaaaaaa8) not located in a known VMA region (needed readable region)!
 destination "%esi" ok
SegvReason: reading unknown VMA
Signal: 11
SourcePackage: nux
StacktraceTop:
 g_datalist_id_set_data_full () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 g_object_unref () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 unity::PanelTray::~PanelTray() () from /usr/lib/compiz/libunityshell.so
 unity::PanelTray::~PanelTray() () from /usr/lib/compiz/libunityshell.so
Title: compiz crashed with SIGSEGV in g_datalist_id_set_data_full()
UpgradeStatus: Upgraded to precise on 2011-07-05 (208 days ago)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

[Robert Ancell (robert-ancell)]

To reproduce:
1. Log in
2. Connect external monitor
3. Once external monitor shows desktop, disconnect it

Expected behaviour:
Second desktop is removed, no changes to existing windows on primary monitor

Observed behaviour:
Screen changes to black for a few seconds, then background shows, then windows are restacked.

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #916228, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.