compiz crashed with SIGSEGV in g_source_unref()

[Maintech]

Binary package hint: compiz

Unity ceased to render correctly on screen so I opened a terminal and entered "unity --reset" and the terminal filled with errors and appaport wanted to report the crash. It has happened exactly the same every time I have repeated the command.

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: compiz-core 1:0.9.4+bzr20110415-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
NonfreeKernelModules: nvidia
.proc.driver.nvidia.agp.gpu:
 Fast Writes: Supported
 SBA: Supported
 AGP Rates: 4x 2x 1x
 Registers: 0x1f000217:0x1f000104
.proc.driver.nvidia.agp.host.bridge:
 Host Bridge: PCI device 8086:2531
 Fast Writes: Supported
 SBA: Supported
 AGP Rates: 4x 2x 1x
 Registers: 0x1f000217:0x00000104
.proc.driver.nvidia.agp.status:
 Status: Enabled
 Driver: AGPGART
 AGP Rate: 4x
 Fast Writes: Disabled
 SBA: Disabled
.proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86 Kernel Module 270.41.03 Sat Apr 9 00:04:57 PDT 2011
 GCC version: gcc version 4.5.2 (Ubuntu/Linaro 4.5.2-8ubuntu3)
Architecture: i386
CompizPlugins: [core,bailer,detection,composite,opengl,decor,mousepoll,vpswitch,regex,animation,snap,expo,move,compiztoolbox,place,grid,imgpng,gnomecompat,wall,ezoom,workarounds,staticswitcher,resize,fade,unitymtgrabhandles,scale,session,unityshell]
CompositorRunning: compiz
CrashCounter: 1
Date: Fri Apr 15 22:47:12 2011
DistUpgraded: Fresh install
DistroCodename: natty
DistroVariant: ubuntu
DkmsStatus: nvidia-current, 270.41.03, 2.6.38-8-generic, i686: installed
EcryptfsInUse: Yes
ExecutablePath: /usr/bin/compiz
GraphicsCard: nVidia Corporation NV40 [GeForce 6800 XT] [10de:0048] (rev a1) (prog-if 00 [VGA controller])
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha i386 (20110329.1)
InstallationMedia_: Ubuntu 11.04 "Natty Narwhal" - Alpha i386 (20110329.1)
JockeyStatus: xorg:nvidia_current - NVIDIA accelerated graphics driver (Proprietary, Enabled, In use)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
MachineType: Dell Computer Corporation Precision WorkStation 530 MT
ProcCmdline: compiz
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic root=UUID=ff9cfdcc-5be1-4991-9b52-9a755845758d ro quiet splash vt.handoff=7
ProcVersionSignature_: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Renderer: Unknown
SegvAnalysis:
 Segfault happened at: 0x671d99 <g_source_unref+25>: mov 0x10(%eax),%edx
 PC (0x00671d99) ok
 source "0x10(%eax)" (0x726f274d) not located in a known VMA region (needed readable region)!
 destination "%edx" ok
SegvReason: reading unknown VMA
Signal: 11
SourcePackage: compiz
StacktraceTop:
 g_source_unref () from /lib/i386-linux-gnu/libglib-2.0.so.0
 Glib::Source::unreference() const () from /usr/lib/libglibmm-2.4.so.1
 PrivateScreen::~PrivateScreen() ()
 PrivateScreen::~PrivateScreen() ()
 CompScreen::~CompScreen() ()
Title: compiz crashed with SIGSEGV in g_source_unref()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare
XsessionErrors: (nautilus:1541): GConf-CRITICAL **: gconf_value_free: assertion `value != NULL' failed
dmi.bios.date: 11/01/2004
dmi.bios.vendor: Dell Computer Corporation
dmi.bios.version: A11
dmi.board.vendor: Dell Computer Corp.
dmi.chassis.type: 6
dmi.chassis.vendor: Dell Computer Corporation
dmi.modalias: dmi:bvnDellComputerCorporation:bvrA11:bd11/01/2004:svnDellComputerCorporation:pnPrecisionWorkStation530MT:pvr:rvnDellComputerCorp.:rn:rvr:cvnDellComputerCorporation:ct6:cvr:
dmi.product.name: Precision WorkStation 530 MT
dmi.sys.vendor: Dell Computer Corporation
version.compiz: compiz 1:0.9.4+bzr20110415-0ubuntu1
version.libdrm2: libdrm2 2.4.23-1ubuntu6
version.libgl1-mesa-dri: libgl1-mesa-dri 7.10.2-0ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.10.2-0ubuntu1
version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
version.xserver-xorg: xserver-xorg 1:7.6+4ubuntu3
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.0-0ubuntu4
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.14.0-4ubuntu7
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110107+b795ca6e-0ubuntu7

[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 #759791, 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.