WARNING: at /build/buildd/linux-2.6.38/drivers/gpu/drm/radeon/radeon_fence.c:248 radeon_fence_wait+0x2ea/0x360 [radeon]()

crash when maximize gedit with grid plugin on top edge 2 times consecutively.

but I have open also so tab in FF, listen music and nautilus open. then I'm not sure what did crash the kernel.

after the second crash the system have freeze and I must reboot with the power button on the laptop.

ProblemType: KernelOops
DistroRelease: Ubuntu 11.04
Package: linux-image-2.6.38-8-generic-pae 2.6.38-8.42
Regression: Yes
Reproducible: Yes
ProcVersionSignature: Ubuntu 2.6.38-8.41-generic-pae 2.6.38.2
Uname: Linux 2.6.38-8-generic-pae i686
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
Annotation: Your system might become unstable now and might need to be restarted.
AplayDevices:
 **** List of PLAYBACK Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC269VB Analog [ALC269VB Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC269VB Analog [ALC269VB Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: steve 31242 F.... pulseaudio
CRDA: Error: [Errno 2] File o directory non esistente
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf8200000 irq 46'
   Mixer name : 'Realtek ALC269VB'
   Components : 'HDA:10ec0269,144dc571,00100100'
   Controls : 15
   Simple ctrls : 9
Date: Tue Apr 12 00:26:11 2011
Failure: oops
HibernationDevice: RESUME=UUID=c6f771fc-3808-4b02-bc1d-365fbcf1c9ba
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha i386 (20110302)
MachineType: SAMSUNG ELECTRONICS CO., LTD. RV410/RV510
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic-pae root=UUID=bb985a30-2987-4a83-8224-bf94ed83284b ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-2.6.38-8-generic-pae N/A
 linux-backports-modules-2.6.38-8-generic-pae N/A
 linux-firmware 1.50
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
SourcePackage: linux
Title: WARNING: at /build/buildd/linux-2.6.38/drivers/gpu/drm/radeon/radeon_fence.c:248 radeon_fence_wait+0x2ea/0x360 [radeon]()
UpgradeStatus: Upgraded to natty on 2011-03-26 (16 days ago)
dmi.bios.date: 08/27/2010
dmi.bios.vendor: Phoenix Technologies Ltd.
dmi.bios.version: 01UK.P028.20100827.LX
dmi.board.name: RV410/RV510
dmi.board.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.board.version: Not Applicable
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.:bvr01UK.P028.20100827.LX:bd08/27/2010:svnSAMSUNGELECTRONICSCO.,LTD.:pnRV410/RV510:pvrNotApplicable:rvnSAMSUNGELECTRONICSCO.,LTD.:rnRV410/RV510:rvrNotApplicable:cvnSAMSUNGELECTRONICSCO.,LTD.:ct10:cvrN/A:
dmi.product.name: RV410/RV510
dmi.product.version: Not Applicable
dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD.