It just happened again, here is the kernel panic report, if it helps anyone diagnose this:
Interval Since Last Panic Report: 1091 sec
Panics Since Last Report: 8
Anonymous UUID: D0B159D8-2609-4514-9F1E-1C42C8BFECB9
Thu Jul 21 10:51:24 2011
Machine-check capabilities (cpu 2) 0x0000000000000c09:
family: 6 model: 37 stepping: 2 microcode: 9
Intel(R) Core(TM) i5 CPU M 540 @ 2.53GHz
9 error-reporting banks
threshold-based error status present
extended corrected memory error handling present
Machine-check status 0x0000000000000004:
machine-check in progress
MCA error-reporting registers:
IA32_MC0_STATUS(0x401): 0x0000000000000800 invalid
IA32_MC1_STATUS(0x405): 0x0000000000000000 invalid
IA32_MC2_STATUS(0x409): 0x0000000000000000 invalid
IA32_MC3_STATUS(0x40d): 0x0000000000000000 invalid
IA32_MC4_STATUS(0x411): 0x0000000000000000 invalid
IA32_MC5_STATUS(0x415): 0x0000000000000000 invalid
IA32_MC6_STATUS(0x419): 0x0000000000000000 invalid
IA32_MC7_STATUS(0x41d): 0x0000000000000000 invalid
Package 0 logged:
IA32_MC8_STATUS(0x421): 0x0000000000000000 invalid
panic(cpu 3 caller 0xffffff80002c2cb5): "Machine Check at 0xffffff7f81e65c6d, registers:\n" "CR0: 0x000000008001003b, CR2: 0xffffff809e769004, CR3: 0x0000000000100000, CR4: 0x0000000000000660\n" "RAX: 0x0000000000000020, RBX: 0x0000000000000000, RCX: 0x0000000000000001, RDX: 0x0000000000000000\n" "RSP: 0xffffff80a0ab3d70, RBP: 0xffffff80a0ab3da0, RSI: 0x0000000000000000, RDI: 0xffffff800c056800\n" "R8: 0xffffff800c010800, R9: 0x0000000000000000, R10: 0x0000000000000000, R11: 0x0000000000000000\n" "R12: 0x00000000000007b0, R13: 0xffffff800be550c0, R14: 0xffffff800c010800, R15: 0x0000000000000006\n" "RFL: 0x0000000000000046, RIP: 0xffffff7f81e65c6d, CS: 0x0000000000000008, SS: 0x0000000000000010\n" "Error code: 0x0000000000000000\n"@/SourceCache/xnu/xnu-1699.22.73/osfmk/i386/trap_native.c:278
Backtrace (CPU 3), Frame : Return Address
0xffffff8076d4eec0 : 0xffffff8000220702
0xffffff8076d4ef40 : 0xffffff80002c2cb5
0xffffff8076d4f0a0 : 0xffffff80002d840f
0xffffff80a0ab3da0 : 0xffffff7f81e5d847
0xffffff80a0ab3e80 : 0xffffff7f81e5f371
0xffffff80a0ab3f30 : 0xffffff80002c41f4
0xffffff80a0ab3f50 : 0xffffff800022d2b5
0xffffff80a0ab3f90 : 0xffffff800022cc1b
0xffffff80a0ab3fb0 : 0xffffff8000820057
Kernel Extensions in backtrace:
com.apple.driver.AppleIntelCPUPowerManagement(166.0)[7FCD8D98-D972-3973-A13B-DC551C536EE6]@0xffffff7f81e5b000->0xffffff7f81e84fff
BSD process name corresponding to current thread: kernel_task
Mac OS version:
11A511
Kernel version:
Darwin Kernel Version 11.0.0: Sat Jun 18 12:56:35 PDT 2011; root:xnu-1699.22.73~1/RELEASE_X86_64
Kernel UUID: 24CC17EB-30B0-3F6C-907F-1A9B2057AF78
System model name: MacBookPro6,1 (Mac-F22589C8)
System uptime in nanoseconds: 19554049249946
last loaded kext at 2442688695589: com.apple.iokit.IOAVBFamily 1.0.0d22 (addr 0xffffff7f8078d000, size 36864)
last unloaded kext at 2504926376501: com.apple.iokit.IOAVBFamily 1.0.0d22 (addr 0xffffff7f8078d000, size 36864)
loaded kexts:
com.apple.filesystems.smbfs 1.7.0
com.apple.driver.AppleHWSensor 1.9.4d0
com.apple.driver.AGPM 100.12.40
com.apple.filesystems.autofs 3.0
com.apple.driver.AppleMikeyHIDDriver 122
com.apple.driver.AppleHDA 2.1.1f11
com.apple.driver.AppleUpstreamUserClient 3.5.9
com.apple.driver.AppleMCCSControl 1.0.24
com.apple.driver.AppleMikeyDriver 2.1.1f11
com.apple.driver.AudioAUUC 1.59
com.apple.driver.AppleIntelHDGraphics 7.0.2
com.apple.driver.AppleIntelHDGraphicsFB 7.0.2
com.apple.driver.SMCMotionSensor 3.0.1d2
com.apple.iokit.IOUserEthernet 1.0.0d1
com.apple.Dont_Steal_Mac_OS_X 7.0.0
com.apple.driver.AudioIPCDriver 1.2.0
com.apple.driver.AppleSMCLMU 2.0.1d2
com.apple.GeForce 7.0.2
com.apple.driver.ACPI_SMC_PlatformPlugin 4.7.0b2
com.apple.driver.AppleMuxControl 3.0.8
com.apple.driver.AppleLPC 1.5.1
com.apple.driver.AppleUSBTCButtons 220.8
com.apple.driver.AppleUSBTCKeyboard 220.8
com.apple.driver.AppleIRController 309
com.apple.iokit.SCSITaskUserClient 3.0.0
com.apple.AppleFSCompression.AppleFSCompressionTypeDataless 1.0.0d1
com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0d1
com.apple.BootCache 32
com.apple.iokit.IOAHCIBlockStorage 2.0.0
com.apple.driver.AppleUSBHub 4.4.0
com.apple.driver.AirPort.Brcm4331 500.20.6
com.apple.iokit.AppleBCM5701Ethernet 3.0.6b9
com.apple.driver.AppleEFINVRAM 1.5.0
com.apple.driver.AppleFWOHCI 4.8.6
com.apple.driver.AppleSmartBatteryManager 161.0.0
com.apple.driver.AppleAHCIPort 2.1.8
com.apple.driver.AppleUSBEHCI 4.4.0
com.apple.driver.AppleACPIButtons 1.4
com.apple.driver.AppleRTC 1.4
com.apple.driver.AppleHPET 1.6
com.apple.driver.AppleSMBIOS 1.7
com.apple.driver.AppleACPIEC 1.4
com.apple.driver.AppleAPIC 1.5
com.apple.driver.AppleIntelCPUPowerManagementClient 166.0.0
com.apple.nke.applicationfirewall 3.0.30
com.apple.security.quarantine 1
com.apple.driver.AppleIntelCPUPowerManagement 166.0.0
com.apple.kext.triggers 1.0
com.apple.driver.DspFuncLib 2.1.1f11
com.apple.driver.AppleSMBusController 1.0.10d0
com.apple.iokit.IOFireWireIP 2.2.3
com.apple.iokit.IOSurface 80.0
com.apple.iokit.IOBluetoothSerialManager 2.5f17
com.apple.iokit.IOSerialFamily 10.0.5
com.apple.iokit.IOAudioFamily 1.8.3fc11
com.apple.kext.OSvKernDSPLib 1.3
com.apple.driver.AppleHDAController 2.1.1f11
com.apple.iokit.IOHDAFamily 2.1.1f11
com.apple.driver.AppleSMC 3.1.1d2
com.apple.driver.IOPlatformPluginFamily 4.7.0b2
com.apple.driver.AppleGraphicsControl 3.0.8
com.apple.driver.AppleSMBusPCI 1.0.10d0
com.apple.driver.AppleBacklightExpert 1.0.3
com.apple.nvidia.nv50hal 7.0.2
com.apple.NVDAResman 7.0.2
com.apple.iokit.IONDRVSupport 2.3
com.apple.iokit.IOGraphicsFamily 2.3
com.apple.driver.BroadcomUSBBluetoothHCIController 2.5f17
com.apple.driver.AppleUSBBluetoothHCIController 2.5f17
com.apple.iokit.IOBluetoothFamily 2.5f17
com.apple.driver.AppleUSBMultitouch 220.23
com.apple.iokit.IOUSBHIDDriver 4.4.0
com.apple.driver.AppleUSBMergeNub 4.4.0
com.apple.driver.AppleUSBComposite 3.9.0
com.apple.iokit.IOSCSIMultimediaCommandsDevice 3.0.0
com.apple.iokit.IOBDStorageFamily 1.6
com.apple.iokit.IODVDStorageFamily 1.6
com.apple.iokit.IOCDStorageFamily 1.7
com.apple.driver.XsanFilter 403
com.apple.iokit.IOAHCISerialATAPI 2.0.0
com.apple.iokit.IOSCSIArchitectureModelFamily 3.0.0
com.apple.iokit.IOUSBUserClient 4.4.0
com.apple.iokit.IO80211Family 400.40
com.apple.iokit.IOEthernetAVBController 1.0.0d5
com.apple.iokit.IONetworkingFamily 2.0
com.apple.iokit.IOFireWireFamily 4.4.3
com.apple.iokit.IOAHCIFamily 2.0.6
com.apple.iokit.IOUSBFamily 4.4.0
com.apple.driver.AppleEFIRuntime 1.5.0
com.apple.iokit.IOHIDFamily 1.7.0
com.apple.iokit.IOSMBusFamily 1.1
com.apple.security.sandbox 165
com.apple.kext.AppleMatch 1.0.0d1
com.apple.security.TMSafetyNet 7
com.apple.driver.DiskImages 326
com.apple.iokit.IOStorageFamily 1.7
com.apple.driver.AppleKeyStore 28.18
com.apple.driver.AppleACPIPlatform 1.4
com.apple.iokit.IOPCIFamily 2.6.5
com.apple.iokit.IOACPIFamily 1.4