I have a 27 inch iMac (Late 2009) and recently have the following error dialogue appear when I switch on the machine and log on:

Interval Since Last Panic Report: 21 sec

Panics Since Last Report: 1

Anonymous UUID: 0337721A-26F4-4A6D-A332-9B218060A1AD

Sat Oct 6 08:00:30 2012

panic(cpu 0 caller 0xffffff7f9e876490): "Kernel stack memory corruption detected"@/SourceCache/xnu/xnu-2050.18.24/libkern/stack_protector.c:37

Backtrace (CPU 0), Frame : Return Address

0xffffff809c3dbd60 : 0xffffff801da1d626

0xffffff809c3dbdd0 : 0xffffff7f9e876490

0xffffff809c3dbe60 : 0xffffff801de3181b

0xffffff809c3dbea0 : 0xffffff801de3133e

0xffffff809c3dbf30 : 0xffffff801de2d2d0

0xffffff809c3dbf70 : 0xffffff801de31e99

0xffffff809c3dbfb0 : 0xffffff801dab26b7

Kernel Extensions in backtrace:

com.apple.driver.AirPort.Atheros40(600.70.23)[2E6077DF-D532-357F-8107-F23BC2C10 F2F]@0xffffff7f9e868000->0xffffff7f9e9b0fff

dependency: com.apple.iokit.IOPCIFamily(2.7.2)[B1B77B26-7984-302F-BA8E-544DD3D75E73]@0xffff ff7f9e050000

dependency: com.apple.iokit.IO80211Family(500.15)[4282DF5A-86B9-3213-B9B1-675FAD842A94]@0xf fffff7f9e7fc000

dependency: com.apple.iokit.IONetworkingFamily(3.0)[28575328-A798-34B3-BD84-D708138EBD17]@0 xffffff7f9e215000

BSD process name corresponding to current thread: kernel_task

Mac OS version:

Not yet set

Kernel version:

Darwin Kernel Version 12.2.0: Sat Aug 25 00:48:52 PDT 2012; root:xnu-2050.18.24~1/RELEASE_X86_64

Kernel UUID: 69A5853F-375A-3EF4-9247-478FD0247333

Kernel slide: 0x000000001d800000

Kernel text base: 0xffffff801da00000

System model name: iMac10,1 (Mac-F2268DC8)

System uptime in nanoseconds: 2489041607

last loaded kext at 745462931: com.apple.driver.AppleIRController 320.15 (addr 0xffffff7f9f6bd000, size 28672)

loaded kexts:

com.rogueamoeba.InstantOn 6.0.0

com.apple.driver.AppleIRController 320.15

com.apple.driver.AppleUSBCardReader 3.1.0

com.apple.driver.CoreStorageFsck 274.7

com.apple.iokit.SCSITaskUserClient 3.5.1

com.apple.driver.AppleFileSystemDriver 3.0.1

com.apple.AppleFSCompression.AppleFSCompressionTypeDataless 1.0.0d1

com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0d1

com.apple.BootCache 34

com.apple.driver.XsanFilter 404

com.apple.iokit.IOAHCIBlockStorage 2.2.2

com.apple.driver.AppleIntelCPUPowerManagementClient 196.0.0

com.apple.driver.AppleFWOHCI 4.9.6

com.apple.driver.AppleUSBHub 5.2.5

com.apple.driver.AppleRTC 1.5

com.apple.driver.AirPort.Atheros40 600.70.23

com.apple.driver.AppleAHCIPort 2.4.1

com.apple.nvenet 2.0.19

com.apple.driver.AppleUSBEHCI 5.4.0

com.apple.driver.AppleUSBOHCI 5.2.5

com.apple.driver.AppleEFINVRAM 1.6.1

com.apple.driver.AppleHPET 1.7

com.apple.driver.AppleACPIButtons 1.6

com.apple.driver.AppleSMBIOS 1.9

com.apple.driver.AppleACPIEC 1.6

com.apple.driver.AppleAPIC 1.6

com.apple.nke.applicationfirewall 4.0.39

com.apple.security.quarantine 2

com.apple.driver.AppleIntelCPUPowerManagement 196.0.0

com.apple.iokit.IOUSBHIDDriver 5.2.5

com.apple.iokit.IOSCSIBlockCommandsDevice 3.5.1

com.apple.iokit.IOUSBMassStorageClass 3.5.0

com.apple.driver.AppleUSBMergeNub 5.2.5

com.apple.driver.AppleUSBComposite 5.2.5

com.apple.iokit.IOSCSIMultimediaCommandsDevice 3.5.1

com.apple.iokit.IOBDStorageFamily 1.7

com.apple.iokit.IODVDStorageFamily 1.7.1

com.apple.iokit.IOCDStorageFamily 1.7.1

com.apple.driver.CoreStorage 274.7

com.apple.iokit.IOAHCISerialATAPI 2.5.0

com.apple.iokit.IOSCSIArchitectureModelFamily 3.5.1

com.apple.iokit.IOFireWireFamily 4.5.5

com.apple.iokit.IOUSBUserClient 5.2.5

com.apple.iokit.IO80211Family 500.15

com.apple.iokit.IOAHCIFamily 2.2.1

com.apple.iokit.IONetworkingFamily 3.0

com.apple.iokit.IOUSBFamily 5.4.0

com.apple.driver.NVSMU 2.2.9

com.apple.driver.AppleEFIRuntime 1.6.1

com.apple.iokit.IOHIDFamily 1.8.0

com.apple.iokit.IOSMBusFamily 1.1

com.apple.security.sandbox 220

com.apple.kext.AppleMatch 1.0.0d1

com.apple.security.TMSafetyNet 7

com.apple.driver.DiskImages 344

com.apple.iokit.IOStorageFamily 1.8

com.apple.driver.AppleKeyStore 28.21

com.apple.driver.AppleACPIPlatform 1.6

com.apple.iokit.IOPCIFamily 2.7.2

com.apple.iokit.IOACPIFamily 1.4

com.apple.kec.corecrypto 1.0

Model: iMac10,1, BootROM IM101.00CC.B00, 2 processors, Intel Core 2 Duo, 3.06 GHz, 4 GB, SMC 1.53f13

Graphics: ATI Radeon HD 4670, ATI Radeon HD 4670, PCIe, 256 MB

Memory Module: BANK 0/DIMM1, 2 GB, DDR3, 1067 MHz, 0x802C, 0x31364A53463235363634485A2D3147314631

Memory Module: BANK 1/DIMM1, 2 GB, DDR3, 1067 MHz, 0x802C, 0x31364A53463235363634485A2D3147314631

AirPort: spairport_wireless_card_type_airport_extreme (0x168C, 0x8F), Atheros 9280: 4.0.70.23-P2P

Bluetooth: Version 4.0.9f33 10885, 2 service, 18 devices, 1 incoming serial ports

Network Service: AirPort, AirPort, en1

Serial ATA Device: ST31000528ASQ, 1 TB

Serial ATA Device: HL-DT-ST DVDRW GA11N

USB Device: Built-in iSight, apple_vendor_id, 0x8502, 0x24400000 / 2

USB Device: Internal Memory Card Reader, apple_vendor_id, 0x8403, 0x26500000 / 2

USB Device: USB Receiver, 0x046d (Logitech Inc.), 0xc52f, 0x04100000 / 3

USB Device: IR Receiver, apple_vendor_id, 0x8242, 0x04500000 / 2

USB Device: BRCM2046 Hub, 0x0a5c (Broadcom Corp.), 0x4500, 0x06100000 / 2

USB Device: Bluetooth USB Host Controller, apple_vendor_id, 0x8215, 0x06110000 / 4