Normally the 'Backtrace' part of a report of a kernel panic will present information that's quite unintelligible.
In this photograph, for example:
![example.png]( "example.png")
For troubleshooting
Readers are more likely to make sense of a backtrace if you set a boot argument – keepsyms=y – in NVRAM.
With Terminal, whilst logged in as an administrator, be prepared to enter the administrator's password then enter the following command:
The first of those two boot arguments (-v) causes the operating system to start and shut down in verbose mode.
For any change to boot arguments to be effective, restart (reboot) the OS.
With symbols: examples of .panic file content
Backtraces are presented in reverse chronological order, so read from bottom to top.
(The examples below exclude the list of loaded kernel extensions – they're irrelevant to this topic.)
Example A: OS X Mavericks
This panic occurred during a check of an HFS Plus file system.
Near the top of the trace there's something obviously related to HFS:
Example B: OS X Yosemite
In this case, the cause of the panic was initially unknown.
Within the backtrace there's a distinctive string:
That string was recognised by someone in Ask Different; the panic was associated with an HFS Plus file system where journalling was unexpectedly disabled.
Related
nvram(8) Mac OS X Manual Page in the Apple Developer Retired Documents Library
How to Reset NVRAM on your Mac – Apple Support
xnu-1228 / Boot Arguments - Tutorials (The Genius Bar) - InsanelyMac Forum (2008-05-25, and captured in the Wayback Machine)
http://fxr.watson.org/fxr/source/osfmk/i386/AT386/model_dep.c?v=xnu-1228#L818
Postscript
The photograph that was originally with this post was lost. Now in its place: an edition of the photograph from example B.
In this photograph, for example:
For troubleshooting
Readers are more likely to make sense of a backtrace if you set a boot argument – keepsyms=y – in NVRAM.
With Terminal, whilst logged in as an administrator, be prepared to enter the administrator's password then enter the following command:
sudo nvram boot-args="-v keepsyms=y"
The first of those two boot arguments (-v) causes the operating system to start and shut down in verbose mode.
For any change to boot arguments to be effective, restart (reboot) the OS.
With symbols: examples of .panic file content
Backtraces are presented in reverse chronological order, so read from bottom to top.
(The examples below exclude the list of loaded kernel extensions – they're irrelevant to this topic.)
Example A: OS X Mavericks
This panic occurred during a check of an HFS Plus file system.
Near the top of the trace there's something obviously related to HFS:
_hfs_vnop_close +
Code:
Anonymous UUID: CA907937-552D-42D6-3F32-C7D13950F0B4
Thu Oct 2 12:50:29 2014
panic(cpu 1 caller 0xffffff800938533e): "lck_rw_unlock(): lock held in mode: 2\n"@/SourceCache/xnu/xnu-2422.115.4/osfmk/i386/locks_i386.c:1259
Backtrace (CPU 1), Frame : Return Address
0xffffff810d22bb50 : 0xffffff8009022f79 mach_kernel : _panic + 0xc9
0xffffff810d22bbd0 : 0xffffff800938533e mach_kernel : _hfs_vnop_close + 0x33e
0xffffff810d22bc30 : 0xffffff80091fe02e mach_kernel : _VNOP_CLOSE + 0xce
0xffffff810d22bca0 : 0xffffff80091f539b mach_kernel : _vn_close + 0x7b
0xffffff810d22bce0 : 0xffffff80091f45bf mach_kernel : _utf8_normalizestr + 0xbbf
0xffffff810d22bd30 : 0xffffff80093c1dec mach_kernel : _closef_locked + 0x13c
0xffffff810d22bda0 : 0xffffff80093c3adb mach_kernel : _fdfree + 0x10b
0xffffff810d22bde0 : 0xffffff80093cf232 mach_kernel : _proc_exit + 0x1d2
0xffffff810d22be60 : 0xffffff80090456b9 mach_kernel : _thread_terminate_self + 0x119
0xffffff810d22be90 : 0xffffff8009048789 mach_kernel : _special_handler + 0xa9
0xffffff810d22bec0 : 0xffffff80090485ee mach_kernel : _act_execute_returnhandlers + 0x7e
0xffffff810d22bef0 : 0xffffff8009020b63 mach_kernel : _ast_taken + 0xe3
0xffffff810d22bf20 : 0xffffff80090dca73 mach_kernel : _i386_astintr + 0x23
0xffffff810d22bf40 : 0xffffff80090f3942 mach_kernel : _return_from_trap + 0xb2
BSD process name corresponding to current thread: fsck_hfs
Boot args: -v keepsyms=y
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: 0x0000000008e00000
Kernel text base: 0xffffff8009000000
System model name: MacBookPro5,2 (Mac-F2268EC8)
System uptime in nanoseconds: 56004494853809
last loaded kext at 55900712405425: com.apple.driver.AppleFireWireStorage 3.4.1 (addr 0xffffff7f8b90d000, size 16384)
last unloaded kext at 41329547225938: com.apple.driver.AppleUSBCDC 4.2.1b5 (addr 0xffffff7f8b82b000, size 16384)
loaded kexts:
…
Model: MacBookPro5,2, BootROM MBP52.008E.B05, 2 processors, Intel Core 2 Duo, 2.66 GHz, 8 GB, SMC 1.42f4
Graphics: NVIDIA GeForce 9400M, NVIDIA GeForce 9400M, PCI, 256 MB
Graphics: NVIDIA GeForce 9600M GT, NVIDIA GeForce 9600M GT, PCIe, 512 MB
Memory Module: BANK 0/DIMM0, 4 GB, DDR3, 1067 MHz, 0x80AD, 0x484D5434353153364D4D5238432D47372020
Memory Module: BANK 1/DIMM0, 4 GB, DDR3, 1067 MHz, 0x80AD, 0x484D5434353153364D4D5238432D47372020
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0x8D), Broadcom BCM43xx 1.0 (5.106.98.100.22)
Bluetooth: Version 4.2.7f3 14616, 3 services, 23 devices, 1 incoming serial ports
Network Service: Ethernet, Ethernet, en0
Network Service: Wi-Fi, AirPort, en1
Serial ATA Device: ST750LX003-1AC154, 750.16 GB
Serial ATA Device: HL-DT-ST DVDRW GS21N
USB Device: Built-in iSight
USB Device: STORE N GO
USB Device: Apple Internal Keyboard / Trackpad
USB Device: IR Receiver
USB Device: Hub in Apple Pro Keyboard
USB Device: Apple Pro Keyboard
USB Device: BRCM2046 Hub
USB Device: Bluetooth USB Host Controller
FireWire Device: fw_target_disk_mode, AAPL, Up to 800 Mb/sec
Thunderbolt Bus:Example B: OS X Yosemite
In this case, the cause of the panic was initially unknown.
Within the backtrace there's a distinctive string:
_NodesAreContiguous
That string was recognised by someone in Ask Different; the panic was associated with an HFS Plus file system where journalling was unexpectedly disabled.
Code:
Anonymous UUID: 936245CB-C37F-6300-8568-D67DB990D759
Wed Nov 5 14:16:23 2014
*** Panic Report ***
panic(cpu 3 caller 0xffffff801c61e80a): Kernel trap at 0xffffff801c30e11b, type 14=page fault, registers:
CR0: 0x000000008001003b, CR2: 0xffffff82068b4000, CR3: 0x000000001f225000, CR4: 0x00000000001626e0
RAX: 0x0000000000000000, RBX: 0xffffff82068b3f48, RCX: 0x0000000076fdd000, RDX: 0x0000000000000000
RSP: 0xffffff82068b3e98, RBP: 0xffffff82068b3ed0, RSI: 0x00000003b7ee8080, RDI: 0xffffff82068b4000
R8: 0x0000000000000000, R9: 0xffffff82069c5000, R10: 0xffffff80202c8f00, R11: 0x0000000d273b7a85
R12: 0x000000000000000c, R13: 0x0000000000000000, R14: 0xffffff803b7ee808, R15: 0xffffff82068b3ea0
RFL: 0x0000000000010202, RIP: 0xffffff801c30e11b, CS: 0x0000000000000008, SS: 0x0000000000000010
Fault CR2: 0xffffff82068b4000, Error code: 0x0000000000000002, Fault CPU: 0x3
Backtrace (CPU 3), Frame : Return Address
0xffffff82068b3b40 : 0xffffff801c53a811 mach_kernel : _panic + 0xd1
0xffffff82068b3bc0 : 0xffffff801c61e80a mach_kernel : _kernel_trap + 0x84a
0xffffff82068b3d80 : 0xffffff801c63a443 mach_kernel : _return_from_trap + 0xe3
0xffffff82068b3da0 : 0xffffff801c30e11b
0xffffff82068b3ed0 : 0xffffff801c97d684 mach_kernel : _NodesAreContiguous + 0x1794
0xffffff82068b3f80 : 0x0
BSD process name corresponding to current thread: kernel_task
Boot args: -v keepsyms=y
Mac OS version:
14A389
Kernel version:
Darwin Kernel Version 14.0.0: Fri Sep 19 00:26:44 PDT 2014; root:xnu-2782.1.97~2/RELEASE_X86_64
Kernel UUID: 89E10306-BC78-3A3B-955C-7C4922577E61
Kernel slide: 0x000000001c200000
Kernel text base: 0xffffff801c400000
__HIB text base: 0xffffff801c300000
System model name: MacBookPro11,1 (Mac-189A3D4F975D5FFC)
System uptime in nanoseconds: 2061441990
last loaded kext at 1497836320: com.apple.driver.CoreStorageFsck 471 (addr 0xffffff7f9e041000, size 106496)
loaded kexts:
…Related
nvram(8) Mac OS X Manual Page in the Apple Developer Retired Documents Library
How to Reset NVRAM on your Mac – Apple Support
xnu-1228 / Boot Arguments - Tutorials (The Genius Bar) - InsanelyMac Forum (2008-05-25, and captured in the Wayback Machine)
http://fxr.watson.org/fxr/source/osfmk/i386/AT386/model_dep.c?v=xnu-1228#L818
Postscript
The photograph that was originally with this post was lost. Now in its place: an edition of the photograph from example B.
Last edited: