compiz crashed with SIGSEGV in g_source_unref()

[MaskedDriver]

Binary package hint: compiz

Every few boot-ups, my windows have no borders and I cannot move windows about the screen. Logging out and back in does not solve the issue. Restarting compiz (compiz --replace) does not work and generates the summaries error message. Nothing but a full restart works.

Release: Ubuntu Natty 11.04 x86_64
Compiz Version: 1:0.9.4git20110322-0ubuntu5
Expected: Boot up Ubuntu, open a program, and have window borders
Happened: Boot up Ubuntu, open a program, no window borders and unable to move windows around

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: compiz-core 1:0.9.4git20110322-0ubuntu5
ProcVersionSignature: Ubuntu 2.6.38-7.39-generic 2.6.38
Uname: Linux 2.6.38-7-generic x86_64
NonfreeKernelModules: nvidia
.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_64 Kernel Module 270.30 Fri Feb 25 14:34:55 PST 2011
 GCC version: gcc version 4.5.2 (Ubuntu/Linaro 4.5.2-6ubuntu5)
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
Date: Tue Mar 29 21:55:21 2011
DistUpgraded: Log time: 2011-03-07 08:35:12.269523
DistroCodename: natty
DistroVariant: ubuntu
DkmsStatus:
 nvidia-current, 270.30, 2.6.38-5-generic, x86_64: installed
 nvidia-current, 270.30, 2.6.38-7-generic, x86_64: installed
ExecutablePath: /usr/bin/compiz
GraphicsCard:
 nVidia Corporation C77 [GeForce 9100M G] [10de:0844] (rev a2) (prog-if 00 [VGA controller])
   Subsystem: Acer Incorporated [ALI] Device [1025:014a]
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429)
InstallationMedia_: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429)
JockeyStatus: xorg:nvidia_current - NVIDIA accelerated graphics driver (Proprietary, Enabled, In use)
MachineType: Acer, inc. Aspire 4530
ProcCmdline: compiz --replace restart
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-7-generic root=UUID=27d9041b-1ab2-4ecc-9060-c54e3818bd13 ro vga=792 splash quiet quiet splash nomodeset video=uvesafb:mode_option=1280x800-24,mtrr=3,scroll=ywrap vt.handoff=7
ProcVersionSignature_: Ubuntu 2.6.38-7.39-generic 2.6.38
Renderer: Unknown
SegvAnalysis:
 Segfault happened at: 0x7f84ab727f45 <g_source_unref+5>: mov 0x20(%rdi),%rsi
 PC (0x7f84ab727f45) ok
 source "0x20(%rdi)" (0x4202cd30000017d) not located in a known VMA region (needed readable region)!
 destination "%rsi" ok
SegvReason: reading unknown VMA
Signal: 11
SourcePackage: compiz
StacktraceTop:
 g_source_unref () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 PrivateScreen::~PrivateScreen() ()
 PrivateScreen::~PrivateScreen() ()
 CompScreen::~CompScreen() ()
 CompScreen::~CompScreen() ()
Title: compiz crashed with SIGSEGV in g_source_unref()
UpgradeStatus: Upgraded to natty on 2011-03-28 (1 days ago)
UserGroups:

dmi.bios.date: 07/06/2009
dmi.bios.vendor: Acer
dmi.bios.version: v1.3336
dmi.board.name: Grasmoor
dmi.board.vendor: Acer, Inc.
dmi.board.version: Not Applicable
dmi.chassis.type: 1
dmi.chassis.vendor: Acer, Inc.
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnAcer:bvrv1.3336:bd07/06/2009:svnAcer,inc.:pnAspire4530:pvrNotApplicable:rvnAcer,Inc.:rnGrasmoor:rvrNotApplicable:cvnAcer,Inc.:ct1:cvrN/A:
dmi.product.name: Aspire 4530
dmi.product.version: Not Applicable
dmi.sys.vendor: Acer, inc.
version.compiz: compiz 1:0.9.4git20110322-0ubuntu5
version.libdrm2: libdrm2 2.4.23-1ubuntu5
version.libgl1-mesa-glx: libgl1-mesa-glx 7.10.1-0ubuntu3
version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
version.xserver-xorg: xserver-xorg 1:7.6~3ubuntu11
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.0-0ubuntu4
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.14.0-4ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110107+b795ca6e-0ubuntu6

[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 #740897, 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.