compiz crashed with SIGSEGV in free()

[Perfecto]

Binary package hint: compiz

Alt+TAB 3 or 4 times when the system is busy

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: compiz-core 1:0.9.4git20110322-0ubuntu5
ProcVersionSignature: Ubuntu 2.6.38-7.38-generic 2.6.38
Uname: Linux 2.6.38-7-generic x86_64
NonfreeKernelModules: nvidia
.proc.driver.nvidia.gpus.0: Error: [Errno 21] Es un directorio: '/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 4.5.2-7ubuntu1)
Architecture: amd64
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
Date: Sat Mar 26 22:49:29 2011
DistUpgraded: Log time: 2011-03-25 17:35:06.993758
DistroCodename: natty
DistroVariant: ubuntu
ExecutablePath: /usr/bin/compiz
GraphicsCard:
 nVidia Corporation G86 [GeForce 8400M GS] [10de:0427] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Samsung Electronics Co Ltd Device [144d:c031]
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Alpha amd64 (20100804)
InstallationMedia_: Ubuntu 10.10 "Maverick Meerkat" - Alpha amd64 (20100804)
JockeyStatus: xorg:nvidia_current - Controlador para tarjetas gráficas NVIDIA (Privativo, Habilitado, En uso)
MachineType: SAMSUNG ELECTRONICS CO., LTD. SR70S/SR71S
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
ProcCmdline: compiz
ProcEnviron:
 LANGUAGE=es_ES:en
 PATH=(custom, user)
 LANG=es_ES.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-7-generic root=UUID=e7380b78-0acc-4589-846b-2e2ea66910ac ro quiet splash vt.handoff=7
ProcVersionSignature_: Ubuntu 2.6.38-7.38-generic 2.6.38
Renderer: Unknown
SegvAnalysis:
 Segfault happened at: 0x7fe6e5adb8c3 <free+83>: lock cmpxchg %esi,(%rbx)
 PC (0x7fe6e5adb8c3) ok
 source "%esi" ok
 destination "(%rbx)" (0x7fe68800001f) not located in a known VMA region (needed writable region)!
SegvReason: writing unknown VMA
Signal: 11
SourcePackage: compiz
StacktraceTop:
 free () from /lib/x86_64-linux-gnu/libc.so.6
 ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 g_variant_unref () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 g_hash_table_unref () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
Title: compiz crashed with SIGSEGV in free()
UpgradeStatus: Upgraded to natty on 2011-03-25 (1 days ago)
UserGroups: adm admin audio avahi avahi-autoipd bin cdrom clamav dialout dip disk fax floppy fuse games gdm lp lpadmin mail netdev ntp operator plugdev pulse pulse-access sambashare saned src ssh sudo tape users usrp video voice www-data
dmi.bios.date: 09/26/2008
dmi.bios.vendor: Phoenix Technologies LTD
dmi.bios.version: 15AB
dmi.board.name: SR70S/SR71S
dmi.board.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnPhoenixTechnologiesLTD:bvr15AB:bd09/26/2008:svnSAMSUNGELECTRONICSCO.,LTD.:pnSR70S/SR71S:pvr15AB:rvnSAMSUNGELECTRONICSCO.,LTD.:rnSR70S/SR71S:rvr:cvnSAMSUNGELECTRONICSCO.,LTD.:ct10:cvrN/A:
dmi.product.name: SR70S/SR71S
dmi.product.version: 15AB
dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD.
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 #743973, 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.