compiz occasionally hangs with 100% cpu

[Eyal]

compiz occasionally hangs and starts getting to 100% cpu.
Screen rendering dies. I noticed that it's usually being triggered when I switch
between workspaces (using the kbd shortcuts Ctrl-Alt-Arrows if it matters)

strace shows endless sched_yield(()
I have to kill X and restart it killing all my active work windows.

This is not a duplicate of #773564 as far as I understand because
it doesn't seem related to the inotify plugin (FileWatcher plugin is disabled in ccsm)

Setup:
Ubuntu 11.04
compiz: 1:0.9.4+bzr20110606-0ubuntu1~natty2

Using Unity
Nvidia Ge Force 210
Using Nvidia proprietary driver

TwinView display

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: compiz 1:0.9.4+bzr20110606-0ubuntu1~natty2
ProcVersionSignature: Ubuntu 2.6.38-12.51-generic-pae 2.6.38.8
Uname: Linux 2.6.38-12-generic-pae i686
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 Kernel Module 270.41.06 Mon Apr 18 14:54:25 PDT 2011
 GCC version: gcc version 4.5.2 (Ubuntu/Linaro 4.5.2-8ubuntu4)
Architecture: i386
CompizPlugins: [core,bailer,detection,composite,opengl,decor,vpswitch,regex,place,move,compiztoolbox,animation,workarounds,resize,mousepoll,imgpng,expo,ezoom,snap,gnomecompat,grid,wall,session,unitymtgrabhandles,staticswitcher,fade,scale,unityshell]
CompositorRunning: compiz
Date: Thu Nov 3 02:08:09 2011
DistUpgraded: Log time: 2011-07-31 23:34:04.020139
DistroCodename: natty
DistroVariant: ubuntu
GraphicsCard:
 nVidia Corporation G98M [Quadro NVS 160M] [10de:06eb] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Dell Device [1028:024f]
JockeyStatus:
 xorg:nvidia_173 - NVIDIA accelerated graphics driver (Proprietary, Disabled, Not in use)
 xorg:nvidia_current - NVIDIA accelerated graphics driver (Proprietary, Disabled, Not in use)
MachineType: Dell Inc. Latitude E6500
PackageArchitecture: all
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: root=UUID=d93f8e2c-9d02-419b-a69f-f3d20fbe8f16 ro quiet splash
ProcVersionSignature_: Ubuntu 2.6.38-12.51-generic-pae 2.6.38.8
Renderer: Unknown
SourcePackage: compiz
UpgradeStatus: Upgraded to natty on 2011-08-01 (93 days ago)
dmi.bios.date: 08/19/2010
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A24
dmi.board.name: 0PP476
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA24:bd08/19/2010:svnDellInc.:pnLatitudeE6500:pvr:rvnDellInc.:rn0PP476:rvr:cvnDellInc.:ct8:cvr:
dmi.product.name: Latitude E6500
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.4+bzr20110606-0ubuntu1~natty2
version.libdrm2: libdrm2 2.4.23-1ubuntu6
version.libgl1-mesa-dri: libgl1-mesa-dri 7.10.2-0ubuntu2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.10.2-0ubuntu2
version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
version.xserver-xorg: xserver-xorg 1:7.6+4ubuntu3.1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.0-0ubuntu4.1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.14.0-4ubuntu7.1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110107+b795ca6e-0ubuntu7

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Daniel van Vugt (vanvugt)]

All, if you experience this bug, could you please:
1. Copy the attached dsctack script to your home directory (before the bug happens).

And then when the hang happens:
1. Switch to a virtual terminal (Ctrl+Alt+F1) and log in.
2. Run: sh ./dstack compiz >> compizstack.txt
    (several times)
3. Go back to compiz (Ctrl+Alt+F7) and wait for the hang to finish, or restart X from the virtual terminal: sudo restart lightdm
4. Attach the file "compizstack.txt" to this bug.

[DavidBriscoe (idbrii)]

During a compiz hang (top reports compiz at 100%), I ran dstack 3 times.

Looks like it's stuck inside of unity::dash::Result::SetupGetters()

[DavidBriscoe (idbrii)]

Is there anything else you need to know? I'm using Unity on Ubuntu 11.10, but not dual monitors. I don't have File Watcher enabled.

[Daniel van Vugt (vanvugt)]

Eyal - I just realized your issue is a duplicate of bug 815996 so I will mark it as such.

David - If your hang is not related to switching workspaces then please log a new bug and attach your dstack output.