MacOS – Kernel panic: need help to confirm or refute the hypotheses about the cause

I recently experienced a kernel panic on my MacBook Pro (OS X version 10.9.5). The crash report is attached below. I did some research on kernel panics, and I figured the VirtualBox kernel extensions would be the obvious suspects. I find it odd, though, given that I wasn't running the VirtualBox app itself. To be sure, I just upgraded VirtualBox.

At any rate, let me explain in a little bit more detail the circumstances of the panic. I had had a Wolfram Mathematica notebook open for quite some time. The crash itself happened while I was browsing a PDF document in Google Chrome. After the panic, OS X automatically restarted and it could restore all windows and apps that were open before the panic, but something weird was happening: both Finder was unresponsive and I didn't have Wi-Fi connection. I also noticed that Mathematica had 7 or 8 grayed-out, unresponsive windows open with the “hourglass” icon superimposed on each of them (not the beach ball, but the icon you usually see under the Apple logo upon startup), instead of the 2 and 3 windows Mathematica had open before the crash (notebook, message panel, and a toolbar). Once I force quit Mathematica, Finder immediately became responsive again and the Wi-Fi connection resumed.

Based on this weird experience, I have three admittedly non-expert hypotheses about what caused the panic:

1. Mathematica exhibited some idiosyncratic, one-time behavior that somehow caused a systemic failure. Perhaps some pathological interaction with the VirtualBox extensions?

2. RAM problems: five months ago, I upgraded the manufacturer-provided 2×2 GB RAM slots to 2×4 GB RAM slots I bought on Amazon (the model had very good reviews) after double-checking it would work with my MBP. Up until today the new RAM seemed to be working properly.

3. Other hardware problems: my MBP is not young (it's an early 2011 model that I bought more than 3.5 years ago), and there may be some mysterious HDD or other hardware failure that began to take its toll.

Given that I had never had kernel panics before and the horror stories I read about their frequent recurrences once they start, it would be very helpful for me to know what was the likely explanation for this panic and what steps I can make to prevent future occurrences. Do you think the description above points to a more definitive cause?

[crash report attached below this line]

Anonymous UUID:       4CABCC7C-02A7-A534-BE98-7EEC1989E170


Mon May  4 04:29:47 2015
panic(cpu 0 caller 0xffffff802d6dc43e): Kernel trap at 0xffffff802da7f789, type 14=page fault, registers:
CR0: 0x0000000080010033, CR2: 0x0000000000008010, CR3: 0x0000000010c78030, CR4: 0x00000000000606e0
RAX: 0x0000000000008010, RBX: 0xffffff8039cb35d0, RCX: 0x00000000031f0000, RDX: 0xffffff803fd0b880
RSP: 0xffffff8039cb3558, RBP: 0xffffff8039cb3580, RSI: 0x0000000000008010, RDI: 0xffffffffffffffff
R8:  0x0000000000000000, R9:  0x000000000000000b, R10: 0x0000000000000000, R11: 0xffffff8055256ea0
R12: 0xffffff8049655a50, R13: 0xffffff804c55d2d0, R14: 0xffffff8039cb35d0, R15: 0x000000000000000b
RFL: 0x0000000000010202, RIP: 0xffffff802da7f789, CS:  0x0000000000000008, SS:  0x0000000000000010
Fault CR2: 0x0000000000008010, Error code: 0x0000000000000002, Fault CPU: 0x0


Backtrace (CPU 0), Frame : Return Address
0xffffff8039cb31e0 : 0xffffff802d622f79
0xffffff8039cb3260 : 0xffffff802d6dc43e
0xffffff8039cb3430 : 0xffffff802d6f3976
0xffffff8039cb3450 : 0xffffff802da7f789
0xffffff8039cb3580 : 0xffffff802d9ba78e
0xffffff8039cb35a0 : 0xffffff802d7ca4b5
0xffffff8039cb3600 : 0xffffff802d7dc691
0xffffff8039cb3650 : 0xffffff802d7dbc30
0xffffff8039cb3690 : 0xffffff802d7e2cf0
0xffffff8039cb36c0 : 0xffffff802d7dab5f
0xffffff8039cb3780 : 0xffffff802d962204
0xffffff8039cb3890 : 0xffffff802d96a83b
0xffffff8039cb3a60 : 0xffffff802d7fd75b
0xffffff8039cb3ac0 : 0xffffff802d7d611b
0xffffff8039cb3b40 : 0xffffff802d7d5a74
0xffffff8039cb3c00 : 0xffffff802d7f1942
0xffffff8039cb3d80 : 0xffffff802d7e9bfc
0xffffff8039cb3f50 : 0xffffff802da40c63
0xffffff8039cb3fb0 : 0xffffff802d6f4176


BSD process name corresponding to current thread: mtmd


Mac OS version:
13F34


Kernel version:
Darwin Kernel Version 13.4.0: Sun Aug 17 19:50:11 PDT 2014; root:xnu-2422.115.4~1/RELEASE_X86_64
Kernel UUID: 9477416E-7BCA-3679-AF97-E1EAAD3DD5A0
Kernel slide:     0x000000002d400000
Kernel text base: 0xffffff802d600000
System model name: MacBookPro8,1 (Mac-94245B3640C91C81)


System uptime in nanoseconds: 855993148177744
last loaded kext at 416759738631165: com.apple.iokit.IOSCSIBlockCommandsDevice 3.6.7 (addr 0xffffff7faf4cc000, size 81920)
last unloaded kext at 419065903612939: com.apple.iokit.IOUSBMassStorageClass 3.6.0 (addr 0xffffff7faf4bb000, size 69632)
loaded kexts:
org.virtualbox.kext.VBoxNetAdp 4.3.20
org.virtualbox.kext.VBoxNetFlt 4.3.20
org.virtualbox.kext.VBoxUSB 4.3.20
org.virtualbox.kext.VBoxDrv 4.3.20
com.apple.driver.AudioAUUC 1.60
com.apple.driver.AppleHWSensor 1.9.5d0
com.apple.driver.AGPM 100.14.34
com.apple.filesystems.autofs 3.0
com.apple.iokit.IOBluetoothSerialManager 4.2.7f3
com.apple.driver.AppleMikeyHIDDriver 124
com.apple.driver.AppleHDA 2.6.3f4
com.apple.iokit.IOUserEthernet 1.0.0d1
com.apple.driver.AppleThunderboltIP 1.1.2
com.apple.driver.AppleBacklight 170.4.11
com.apple.driver.AppleMikeyDriver 2.6.3f4
com.apple.driver.AppleSMCLMU 2.0.4d1
com.apple.driver.ApplePolicyControl 3.6.22
com.apple.driver.ACPI_SMC_PlatformPlugin 1.0.0
com.apple.iokit.BroadcomBluetoothHostControllerUSBTransport 4.2.7f3
com.apple.driver.AppleUpstreamUserClient 3.5.13
com.apple.driver.AppleMCCSControl 1.2.5
com.apple.Dont_Steal_Mac_OS_X 7.0.0
com.apple.driver.AppleHWAccess 1
com.apple.driver.AppleSMCPDRC 1.0.0
com.apple.driver.AppleLPC 1.7.0
com.apple.driver.AppleIntelHD3000Graphics 8.2.4
com.apple.driver.AppleIntelSNBGraphicsFB 8.2.4
com.apple.driver.SMCMotionSensor 3.0.4d1
com.apple.driver.AppleUSBTCButtons 240.2
com.apple.driver.AppleUSBTCKeyboard 240.2
com.apple.driver.AppleIRController 325.7
com.apple.AppleFSCompression.AppleFSCompressionTypeDataless 1.0.0d1
com.apple.AppleFSCompression.AppleFSCompressionTypeLZVN 1.0.0d1
com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0d1
com.apple.BootCache 35
com.apple.iokit.SCSITaskUserClient 3.6.7
com.apple.driver.XsanFilter 404
com.apple.iokit.IOAHCIBlockStorage 2.6.0
com.apple.driver.AppleUSBHub 683.4.0
com.apple.iokit.AppleBCM5701Ethernet 3.8.1b2
com.apple.driver.AppleSmartBatteryManager 161.0.0
com.apple.driver.AppleSDXC 1.5.2
com.apple.driver.AirPort.Brcm4331 700.20.22
com.apple.driver.AppleFWOHCI 5.0.2
com.apple.driver.AppleAHCIPort 3.0.5
com.apple.driver.AppleUSBEHCI 660.4.0
com.apple.driver.AppleACPIButtons 2.0
com.apple.driver.AppleRTC 2.0
com.apple.driver.AppleHPET 1.8
com.apple.driver.AppleSMBIOS 2.1
com.apple.driver.AppleACPIEC 2.0
com.apple.driver.AppleAPIC 1.7
com.apple.driver.AppleIntelCPUPowerManagementClient 217.92.1
com.apple.nke.applicationfirewall 153
com.apple.security.quarantine 3
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com.apple.AppleGraphicsDeviceControl 3.6.22
com.apple.kext.triggers 1.0
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com.apple.vecLib.kext 1.0.0
com.apple.iokit.IOAudioFamily 1.9.7fc2
com.apple.kext.OSvKernDSPLib 1.14
com.apple.iokit.IOSurface 91.1
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com.apple.driver.AppleHDAController 2.6.3f4
com.apple.iokit.IOHDAFamily 2.6.3f4
com.apple.driver.AppleBacklightExpert 1.0.4
com.apple.driver.AppleGraphicsControl 3.6.22
com.apple.driver.IOPlatformPluginLegacy 1.0.0
com.apple.iokit.IOBluetoothHostControllerUSBTransport 4.2.7f3
com.apple.driver.AppleSMBusPCI 1.0.12d1
com.apple.driver.AppleSMBusController 1.0.12d1
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com.apple.iokit.IONDRVSupport 2.4.1
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com.apple.driver.AppleThunderboltDPInAdapter 3.1.7
com.apple.driver.AppleThunderboltDPAdapterFamily 3.1.7
com.apple.driver.AppleThunderboltPCIDownAdapter 1.4.5
com.apple.driver.AppleUSBMultitouch 240.10
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com.apple.iokit.IODVDStorageFamily 1.7.1
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com.apple.iokit.IOAHCISerialATAPI 2.6.1
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com.apple.driver.mDNSOffloadUserClient 1.0.1b5
com.apple.iokit.IO80211Family 640.36
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com.apple.iokit.IOAHCIFamily 2.6.5
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