Kernel panic. Can anyone tell me what caused it?

My Macbook Pro has been having a lot of kernel panics recently, especially when I try to shut it down: It restarts before it can go off.

Can anyone pinpoint the hardware or software responsible? Here is the error report from the last one:

Anonymous UUID: 5FBADF08-3C68-9E27-E8BD-D3472494127F

Wed Apr 29 23:42:13 2015

*** Panic Report ***

panic(cpu 2 caller 0xffffff802a617cc2): Kernel trap at 0xffffff802a5361e0, type 13=general protection, registers:

CR0: 0x000000008001003b, CR2: 0x000000010a749000, CR3: 0x000000002b7d7002, CR4: 0x00000000001626e0

RAX: 0x0000000000000000, RBX: 0xc0ffee845f428944, RCX: 0xffffff8034a726a0, RDX: 0x0000000000001000

RSP: 0xffffff80c6ddb580, RBP: 0xffffff80c6ddb5a0, RSI: 0x0000000000000003, RDI: 0xc0ffee845f428944

R8: 0x0000000000000000, R9: 0x0000000000000000, R10: 0x0000000003a6c000, R11: 0x00007fff7f003000

R12: 0xffffff8036a72ad0, R13: 0xffffff8037152400, R14: 0x0000000000000004, R15: 0x0000000000000003

RFL: 0x0000000000010206, RIP: 0xffffff802a5361e0, CS: 0x0000000000000008, SS: 0x0000000000000010

Fault CR2: 0x000000010a749000, Error code: 0x0000000000000000, Fault CPU: 0x2

Backtrace (CPU 2), Frame : Return Address

0xffffff80bd59de10 : 0xffffff802a52bda1

0xffffff80bd59de90 : 0xffffff802a617cc2

0xffffff80bd59e050 : 0xffffff802a634b73

0xffffff80bd59e070 : 0xffffff802a5361e0

0xffffff80c6ddb5a0 : 0xffffff802a5ffbb4

0xffffff80c6ddb660 : 0xffffff802a601fe7

0xffffff80c6ddb680 : 0xffffff802a591918

0xffffff80c6ddb6c0 : 0xffffff802a5928e3

0xffffff80c6ddbae0 : 0xffffff802a591ae5

0xffffff80c6ddbb40 : 0xffffff802a9fdb4e

0xffffff80c6ddbb70 : 0xffffff802a747659

0xffffff80c6ddbbf0 : 0xffffff802a74728a

0xffffff80c6ddbc40 : 0xffffff802a741905

0xffffff80c6ddbcb0 : 0xffffff802a74c7ca

0xffffff80c6ddbd50 : 0xffffff802a748113

0xffffff80c6ddbd80 : 0xffffff802a742e24

0xffffff80c6ddbdf0 : 0xffffff802a9d5f5e

0xffffff80c6ddbec0 : 0xffffff802a9e7069

0xffffff80c6ddbf50 : 0xffffff802aa4ba86

0xffffff80c6ddbfb0 : 0xffffff802a635376

BSD process name corresponding to current thread: launchd

Mac OS version:

14D136

Kernel version:

Darwin Kernel Version 14.3.0: Mon Mar 23 11:59:05 PDT 2015; root:xnu-2782.20.48~5/RELEASE_X86_64

Kernel UUID: 4B3A11F4-77AA-3D27-A22D-81A1BC5B504D

Kernel slide: 0x000000002a200000

Kernel text base: 0xffffff802a400000

__HIB text base: 0xffffff802a300000

System model name: MacBookPro9,2 (Mac-6F01561E16C75D06)

System uptime in nanoseconds: 48704724760399

last loaded kext at 45991772019539: com.apple.driver.AppleUSBCDC 4.3.3b1 (addr 0xffffff7facd73000, size 20480)

last unloaded kext at 46103581099429: com.apple.driver.AppleUSBCDC 4.3.3b1 (addr 0xffffff7facd73000, size 16384)

loaded kexts:

com.apple.nke.pppoe 1.9

com.apple.driver.AudioAUUC 1.70

com.apple.driver.AGPM 110.19.5

com.apple.driver.X86PlatformShim 1.0.0

com.apple.filesystems.autofs 3.0

com.apple.iokit.IOBluetoothSerialManager 4.3.4f4

com.apple.driver.AppleOSXWatchdog 1

com.apple.driver.AppleMikeyHIDDriver 124

com.apple.driver.AppleHDA 272.18

com.apple.driver.AppleUpstreamUserClient 3.6.1

com.apple.driver.AppleMikeyDriver 272.18

com.apple.iokit.IOUserEthernet 1.0.1

com.apple.driver.AppleIntelHD4000Graphics 10.0.6

com.apple.Dont_Steal_Mac_OS_X 7.0.0

com.apple.driver.AppleHWAccess 1

com.apple.driver.AppleThunderboltIP 2.0.2

com.apple.driver.AppleHV 1

com.apple.driver.AppleBacklight 170.7.4

com.apple.driver.AppleMCCSControl 1.2.11

com.apple.driver.AppleSMCPDRC 1.0.0

com.apple.driver.AppleSMCLMU 2.0.7d0

com.apple.driver.AppleLPC 1.7.3

com.apple.driver.AppleIntelSlowAdaptiveClocking 4.0.0

com.apple.iokit.BroadcomBluetoothHostControllerUSBTransport 4.3.4f4

com.apple.driver.AppleIntelFramebufferCapri 10.0.6

com.apple.driver.SMCMotionSensor 3.0.4d1

com.apple.driver.AppleUSBTCButtons 240.2

com.apple.driver.AppleIRController 327.5

com.apple.driver.AppleUSBTCKeyboard 240.2

com.apple.AppleFSCompression.AppleFSCompressionTypeDataless 1.0.0d1

com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0d1

com.apple.BootCache 36

com.apple.iokit.SCSITaskUserClient 3.7.5

com.apple.driver.XsanFilter 404

com.apple.iokit.IOAHCIBlockStorage 2.7.1

com.apple.driver.AppleFWOHCI 5.5.2

com.apple.driver.AppleUSBHub 705.4.2

com.apple.driver.AirPort.Brcm4360 930.37.3

com.apple.iokit.AppleBCM5701Ethernet 10.1.3

com.apple.driver.AppleSDXC 1.6.5

com.apple.driver.AppleAHCIPort 3.1.2

com.apple.driver.AppleUSBEHCI 705.4.14

com.apple.driver.AppleUSBXHCI 710.4.11

com.apple.driver.AppleRTC 2.0

com.apple.driver.AppleACPIButtons 3.1

com.apple.driver.AppleSmartBatteryManager 161.0.0

com.apple.driver.AppleHPET 1.8

com.apple.driver.AppleSMBIOS 2.1

com.apple.driver.AppleACPIEC 3.1

com.apple.driver.AppleAPIC 1.7

com.apple.driver.AppleIntelCPUPowerManagementClient 218.0.0

com.apple.nke.applicationfirewall 161

com.apple.security.quarantine 3

com.apple.security.TMSafetyNet 8

com.apple.driver.AppleIntelCPUPowerManagement 218.0.0

com.apple.nke.ppp 1.9

com.apple.kext.triggers 1.0

com.apple.iokit.IOSerialFamily 11

com.apple.driver.DspFuncLib 272.18

com.apple.kext.OSvKernDSPLib 1.15

com.apple.iokit.IOSurface 97.4

com.apple.driver.AppleSMBusController 1.0.13d1

com.apple.driver.AppleHDAController 272.18

com.apple.iokit.IOHDAFamily 272.18

com.apple.iokit.IOAudioFamily 203.3

com.apple.vecLib.kext 1.2.0

com.apple.iokit.IOFireWireIP 2.2.6

com.apple.driver.AppleSMBusPCI 1.0.12d1

com.apple.driver.AppleBacklightExpert 1.1.0

com.apple.iokit.IONDRVSupport 2.4.1

com.apple.driver.X86PlatformPlugin 1.0.0

com.apple.driver.IOPlatformPluginFamily 5.9.1d7

com.apple.iokit.IOSlowAdaptiveClockingFamily 1.0.0

com.apple.iokit.IOBluetoothHostControllerUSBTransport 4.3.4f4

com.apple.iokit.IOBluetoothFamily 4.3.4f4

com.apple.iokit.IOUSBUserClient 705.4.0

com.apple.iokit.IOAcceleratorFamily2 156.14

com.apple.AppleGraphicsDeviceControl 3.10.22

com.apple.iokit.IOGraphicsFamily 2.4.1

com.apple.driver.AppleSMC 3.1.9

com.apple.driver.AppleUSBMultitouch 245.2

com.apple.iokit.IOUSBHIDDriver 705.4.0

com.apple.driver.AppleUSBMergeNub 705.4.0

com.apple.driver.AppleUSBComposite 705.4.9

com.apple.driver.CoreStorage 471.20.7

com.apple.iokit.IOSCSIMultimediaCommandsDevice 3.7.5

com.apple.iokit.IOBDStorageFamily 1.7

com.apple.iokit.IODVDStorageFamily 1.7.1

com.apple.iokit.IOCDStorageFamily 1.7.1

com.apple.driver.AppleThunderboltDPInAdapter 4.0.6

com.apple.driver.AppleThunderboltDPAdapterFamily 4.0.6

com.apple.driver.AppleThunderboltPCIDownAdapter 2.0.2

com.apple.iokit.IOAHCISerialATAPI 2.6.1

com.apple.iokit.IOSCSIArchitectureModelFamily 3.7.5

com.apple.iokit.IOFireWireFamily 4.5.6

com.apple.driver.AppleThunderboltNHI 3.1.7

com.apple.iokit.IOThunderboltFamily 4.2.2

com.apple.iokit.IO80211Family 730.60

com.apple.iokit.IOEthernetAVBController 1.0.3b3

com.apple.driver.mDNSOffloadUserClient 1.0.1b8

com.apple.iokit.IONetworkingFamily 3.2

com.apple.iokit.IOAHCIFamily 2.7.5

com.apple.iokit.IOUSBFamily 720.4.4

com.apple.driver.AppleEFINVRAM 2.0

com.apple.driver.AppleEFIRuntime 2.0

com.apple.iokit.IOHIDFamily 2.0.0

com.apple.iokit.IOSMBusFamily 1.1

com.apple.security.sandbox 300.0

com.apple.kext.AppleMatch 1.0.0d1

com.apple.driver.AppleKeyStore 2

com.apple.driver.AppleMobileFileIntegrity 1.0.5

com.apple.driver.AppleCredentialManager 1.0

com.apple.driver.DiskImages 396

com.apple.iokit.IOStorageFamily 2.0

com.apple.iokit.IOReportFamily 31

com.apple.driver.AppleFDEKeyStore 28.30

com.apple.driver.AppleACPIPlatform 3.1

com.apple.iokit.IOPCIFamily 2.9

com.apple.iokit.IOACPIFamily 1.4

com.apple.kec.corecrypto 1.0

com.apple.kec.Libm 1

com.apple.kec.pthread 1

Model: MacBookPro9,2, BootROM MBP91.00D3.B09, 2 processors, Intel Core i5, 2.5 GHz, 4 GB, SMC 2.2f44

Graphics: Intel HD Graphics 4000, Intel HD Graphics 4000, Built-In

Memory Module: BANK 0/DIMM0, 2 GB, DDR3, 1600 MHz, 0x80AD, 0x484D54333235533643465238432D50422020

Memory Module: BANK 1/DIMM0, 2 GB, DDR3, 1600 MHz, 0x80AD, 0x484D54333235533643465238432D50422020

AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0xF5), Broadcom BCM43xx 1.0 (7.15.166.24.3)

Bluetooth: Version 4.3.4f4 15601, 3 services, 18 devices, 1 incoming serial ports

Network Service: Ethernet, Ethernet, en0

Network Service: Wi-Fi, AirPort, en1

Serial ATA Device: APPLE HDD HTS545050A7E362, 500.11 GB

Serial ATA Device: MATSHITADVD-R UJ-8A8, 687.2 MB

USB Device: Hub

USB Device: Hub

USB Device: Apple Internal Keyboard / Trackpad

USB Device: BRCM20702 Hub

USB Device: Bluetooth USB Host Controller

USB Device: IR Receiver

USB Device: USB Optical Mouse

USB Device: Hub

USB Device: FaceTime HD Camera (Built-in)

Thunderbolt Bus: MacBook Pro, Apple Inc., 25.1