compiz crashed with SIGSEGV in sigc::signal_base::impl()

[mike culford]

Changing settings in CCSM and it froze the desktop for a moment then the open windows all vanished momentarily. When all windows reappeared the changes were applied and working properly. This happened twice. Once when enabling wobbly windows and again when enabling the ring switcher. Both times the error report window came up before all the open windows flashed off and back on. It seems the "crash" in this case is only momentary and the changes I was making in CCSM were applied.

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: unity 4.12.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-10.16-generic 3.0.4
Uname: Linux 3.0.0-10-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
CrashCounter: 1
Date: Thu Sep 8 01:14:03 2011
EcryptfsInUse: Yes
ExecutablePath: /usr/bin/compiz
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
ProcCmdline: compiz
ProcEnviron:
 LANGUAGE=en_CA:en
 PATH=(custom, no user)
 LANG=en_CA.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x7f59994062ae <_ZNK4sigc11signal_base4implEv+14>: mov 0x8(%rdi),%rbx
 PC (0x7f59994062ae) ok
 source "0x8(%rdi)" (0x000000f8) not located in a known VMA region (needed readable region)!
 destination "%rbx" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: unity
StacktraceTop:
 sigc::signal_base::impl() const () from /usr/lib/libsigc-2.0.so.0
 sigc::signal_base::connect(sigc::slot_base const&) () from /usr/lib/libsigc-2.0.so.0
 UnityScreen::UnityScreen(CompScreen*) () from /usr/lib/compiz/libunityshell.so
 PluginClassHandler<UnityScreen, CompScreen, 0>::get(CompScreen*) () from /usr/lib/compiz/libunityshell.so
 CompPlugin::VTableForScreenAndWindow<UnityScreen, UnityWindow>::initScreen(CompScreen*) () from /usr/lib/compiz/libunityshell.so
Title: compiz crashed with SIGSEGV in sigc::signal_base::impl()
UpgradeStatus: Upgraded to oneiric on 2011-09-08 (0 days ago)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make Ubuntu better. This particular crash has already been reported and is a duplicate of bug #831769, 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.