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

[Chenheting]

Binary package hint: unity

When I enabled the compiz effect, screen blank a few second and got this bug report to send.

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: unity 3.8.6-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
Architecture: i386
CrashCounter: 1
Date: Fri Apr 15 06:28:15 2011
ExecutablePath: /usr/bin/compiz
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Beta i386 (20110330)
ProcCmdline: compiz
ProcEnviron:
 LANGUAGE=en_SG:en
 LANG=en_SG.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x94fe3d <_ZNK4sigc11signal_base4implEv+29>: mov 0x4(%edi),%esi
 PC (0x0094fe3d) ok
 source "0x4(%edi)" (0x0000007c) not located in a known VMA region (needed readable region)!
 destination "%esi" 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
 CompPlugin::VTableForScreenAndWindow<UnityScreen, UnityWindow>::initScreen(CompScreen*) () from /usr/lib/compiz/libunityshell.so
 CompManager::initPlugin(CompPlugin*) ()
Title: compiz crashed with SIGSEGV in sigc::signal_base::impl()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

[Apport retracing service (apport)]

StacktraceTop:
 sigc::signal_base::impl (this=0x78) at ../../sigc++/signal_base.cc:145
 sigc::signal_base::connect (this=0x78, slot_=...) at ../../sigc++/signal_base.cc:122
 PluginClassHandler<UnityScreen, CompScreen, 0>::PluginClassHandler(CompScreen*) () from /usr/lib/compiz/libunityshell.so
 PlacesHomeView::CreateShortcutFromExec(char const*, char const*, std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >&) () from /usr/lib/compiz/libunityshell.so
 CompManager::initPlugin(CompPlugin*) ()