compiz crashed with SIGSEGV in unity::ui::EdgeBarrierController::Impl::OnPointerBarrierEvent()

[Scott Morningstar]

This happened on a Lenovo T520 laptop using the Intel video drivers. I suspended my laptop with no external screen attached. I woke up the laptop with my external monitor connected to the VGA port but the monitor was turned off. When I powered on the monitor and tried to move a window to the external monitor the window got stuck half way. Now I can not alt tab to the open windows on my laptop screen.

I know you need more information than this but I am not sure what to give you. I am happy to send logs or diagnostic output but I need to restart my laptop now so I can work.

Thanks for looking at this.

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: unity 5.10.0-0ubuntu4
ProcVersionSignature: Ubuntu 3.2.0-23.36-generic 3.2.14
Uname: Linux 3.2.0-23-generic x86_64
ApportVersion: 2.0.1-0ubuntu4
Architecture: amd64
CrashCounter: 1
Date: Tue Apr 17 07:51:16 2012
Disassembly: => 0x0: Cannot access memory at address 0x0
ExecutablePath: /usr/bin/compiz
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120301)
ProcCmdline: compiz
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/zsh
SegvAnalysis:
 Segfault happened at: 0x0: Cannot access memory at address 0x0
 PC (0x00000000) not located in a known VMA region (needed executable region)!
SegvReason: executing NULL VMA
Signal: 11
SourcePackage: unity
StacktraceTop:
 ?? ()
 unity::ui::EdgeBarrierController::Impl::OnPointerBarrierEvent(unity::ui::PointerBarrierWrapper*, std::shared_ptr<unity::ui::BarrierEvent>) () from /usr/lib/compiz/libunityshell.so
 sigc::internal::slot_call2<sigc::bound_mem_functor2<void, unity::ui::EdgeBarrierController::Impl, unity::ui::PointerBarrierWrapper*, std::shared_ptr<unity::ui::BarrierEvent> >, void, unity::ui::PointerBarrierWrapper*, std::shared_ptr<unity::ui::BarrierEvent> >::call_it(sigc::internal::slot_rep*, unity::ui::PointerBarrierWrapper* const&, std::shared_ptr<unity::ui::BarrierEvent> const&) () from /usr/lib/compiz/libunityshell.so
 unity::ui::PointerBarrierWrapper::EmitCurrentData() () from /usr/lib/compiz/libunityshell.so
 ?? () from /usr/lib/compiz/libunityshell.so
Title: compiz crashed with SIGSEGV in unity::ui::EdgeBarrierController::Impl::OnPointerBarrierEvent()
UpgradeStatus: Upgraded to precise on 2012-04-11 (6 days ago)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo

[Apport retracing service (apport)]

StacktraceTop:
 ?? ()
 unity::ui::EdgeBarrierController::Impl::OnPointerBarrierEvent (this=0x2defcc0, owner=0x3b26650, event=...) at /build/buildd/unity-5.10.0/plugins/unityshell/src/EdgeBarrierController.cpp:139
 operator() (_A_a2=<optimized out>, _A_a1=<optimized out>, this=<optimized out>) at /usr/include/sigc++-2.0/sigc++/functors/mem_fun.h:1917
 operator()<unity::ui::PointerBarrierWrapper* const&, const std::shared_ptr<unity::ui::BarrierEvent>&> (_A_arg2=<optimized out>, _A_arg1=<optimized out>, this=<optimized out>) at /usr/include/sigc++-2.0/sigc++/adaptors/adaptor_trait.h:103
 sigc::internal::slot_call2<sigc::bound_mem_functor2<void, unity::ui::EdgeBarrierController::Impl, unity::ui::PointerBarrierWrapper*, std::shared_ptr<unity::ui::BarrierEvent> >, void, unity::ui::PointerBarrierWrapper*, std::shared_ptr<unity::ui::BarrierEvent> >::call_it (rep=<optimized out>, a_1=<optimized out>, a_2=<optimized out>) at /usr/include/sigc++-2.0/sigc++/functors/slot.h:173