Here is another of these false GPU lockup bugs.  Guessing this is a dupe of #39947, but filing separately for your comparison purposes.  Forwarding from launchpad user mpt:

 https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/816337

This particular individual has had this same experience for a couple years or so now, and has filed a few dozen reports about it.  Previously we had thought it was a conflict with vesafb but you can see from the logs that there are no other framebuffer drivers loaded.  I'm wondering if it's something peculiar with his hardware, although we've seen reports like this from other various people too (I'll file a few others if they look interesting).

Apport says:

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: xserver-xorg-video-intel 2:2.15.0-3ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-7.8-generic 3.0.0
Uname: Linux 3.0.0-7-generic x86_64
Architecture: amd64
Chipset: i965gm
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
Date: Tue Jul 26 10:52:28 2011
DistUpgraded: Fresh install
DistroCodename: oneiric
DistroVariant: ubuntu
DuplicateSignature: [i965gm] GPU lockup EIR: 0x00000010 PGTBL_ER: 0x00000100 Ubuntu 11.10
ExecutablePath: /usr/share/apport/apport-gpu-error-intel.py
ExtraDebuggingInterest: Yes, whatever it takes to get this fixed in Ubuntu
GraphicsCard:
 Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (primary) [8086:2a02] (rev 03) (prog-if 00 [VGA controller])
   Subsystem: Apple Computer Inc. Device [106b:00a1]
   Subsystem: Apple Computer Inc. Device [106b:00a1]
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha amd64+mac (20110705.1)
InterpreterPath: /usr/bin/python2.7
MachineType: Apple Inc. MacBook4,1
ProcCmdline: /usr/bin/python /usr/share/apport/apport-gpu-error-intel.py
ProcEnviron:

ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.0.0-7-generic root=UUID=dd41ef42-12f2-42cb-80ce-fc52d9f2c3d0 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 xserver-xorg 1:7.6+7ubuntu6
 libdrm2 2.4.26-1ubuntu1
 xserver-xorg-video-intel 2:2.15.0-3ubuntu2
SourcePackage: xserver-xorg-video-intel
Title: [i965gm] GPU lockup EIR: 0x00000010 PGTBL_ER: 0x00000100
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

dmi.bios.date: 02/09/08
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MB41.88Z.00C1.B00.0802091535
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Mac-F22788A9
dmi.board.vendor: Apple Inc.
dmi.board.version: PVT
dmi.chassis.asset.tag: Asset Tag#
dmi.chassis.type: 2
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-F22788A9
dmi.modalias: dmi:bvnAppleInc.:bvrMB41.88Z.00C1.B00.0802091535:bd02/09/08:svnAppleInc.:pnMacBook4,1:pvr1.0:rvnAppleInc.:rnMac-F22788A9:rvrPVT:cvnAppleInc.:ct2:cvrMac-F22788A9:
dmi.product.name: MacBook4,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.
peripherals:
 /desktop/gnome/peripherals/mouse:
   cursor_theme = DMZ-White
version.compiz: compiz 1:0.9.5.0-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.26-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 7.11~1-0ubuntu4
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.11~1-0ubuntu4
version.xserver-xorg: xserver-xorg 1:7.6+7ubuntu6
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.6.0-1ubuntu13
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.2-1ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.15.0-3ubuntu2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110411+8378443-1