What is a Kernel Panic and what does it mean?

Question

I have this report:

Anonymous UUID:       Removed

Tue Aug 11 20:26:13 2015

*** Panic Report ***
panic(cpu 2 caller 0xffffff8028bc1cde): "launchd died\nState at Last Exception:\n\n"@/SourceCache/xnu/xnu-2782.20.48/bsd/kern/kern_exit.c:363

uuid info:
 0x7fff658c1000 uuid = <65dccb06-339c-3e25-9702-600a28291d0e>
 0x10f26f000    uuid = <7f885d63-b284-3471-b6e3-172489232c37>
 0x10f2c1000    uuid = <4396b358-725e-3ec0-bcbb-e4bf75fe1fb0>

RAX: 0x0000000002000001, RBX: 0x0000000000000006, RCX: 0x000000010ff8c0e8, RDX: 0x0000000000000000
RSP: 0x000000010ff8c0e8, RBP: 0x000000010ff8c190, RSI: 0x000000010ff8bf40, RDI: 0x0000000000000001
R8:  0x0000000000000000, R9:  0x000000010f2ae9f0, R10: 0x00007fff9899bb02, R11: 0x0000000000000206
R12: 0x0000000000000000, R13: 0x00007fff8e2f97e0, R14: 0x000000010ff8c5d0, R15: 0x000000010ff8c790
RFL: 0x0000000000000206, RIP: 0x00007fff9899995a, CS:  0x0000000000000007, SS:  0x0000000000000023

Thread  0xffffff803414bc50
    0x00007fff929c1f4b
    0x00007fff929c2068
    0x00007fff929bb554
    0x00007fff968a8a6c
    0x000000010f29d8f7
    0x00007fff97d71c13
    0x00007fff97d7488f
    0x00007fff97d82fe4
    0x00007fff8b16b637
    0x00007fff8b16940d
    0x0000000000000000

Thread  0xffffff80342d7108
    0x00007fff97d74a6a
    0x0000000000000000

Thread  0xffffff80341a8e28
      Could not read LR from frame at 0x000000010fd03dc8

Thread  0xffffff8034130798
    0x00007fff97d823ad
    0x0000000000000000

Thread  0xffffff8035ac05c0
    0x00007fff97d7c87e
    0x00007fff97d7562b
    0x00007fff97d75154
    0x00007fff97d76ecc
    0x00007fff97d746b7
    0x00007fff97d74453
    0x00007fff8b16b268
    0x00007fff8b16b1e5
    0x00007fff8b16941d
    0x0000000000000000

Thread  0xffffff803523de28
    0x000000010f28e28b
    0x000000010f28ceb9
    0x000000010f29d5ca
    0x000000010f29d82e
    0x00007fff97d71c13
    0x00007fff97d7c87e
    0x00007fff97d7562b
    0x00007fff97d75154
    0x00007fff97d76ecc
    0x00007fff97d746b7
    0x00007fff97d82fe4
    0x00007fff8b16b637
    0x00007fff8b16940d
    0x0000000000000000

Thread  0xffffff803d8442e0
    0x00007fff8b28ef1a
    0x0000000000000001
    0x00007fff658cd455
    0x00007fff8b3567b5
    0x00007fff929907e8
    0x00007fff8e2f97e0
    0x00007fff8e2fbddf
    0x00007fff97d71c13
    0x00007fff97d72e5e
    0x00007fff8e2fa0a7
    0x000000010f29a383
    0x00007fff97d71c13
    0x00007fff97d75365
    0x00007fff97d76ecc
    0x00007fff97d75154
    0x00007fff97d76ecc
    0x00007fff97d746b7
    0x00007fff97d82fe4
    0x00007fff8b16b637
    0x00007fff8b16940d
    0x0000000000000000

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

What is a kernel panic?

Answer 1

In general, a kernel panic is defined by Apple as "In UNIX, a panic is an unrecoverable system error detected by the kernel."

• That quote comes from Apple's Technical Note TN2063: Understanding and Debugging Kernel Panics

In your specific case, the main program that starts and stops everything else on the system has an unrecoverable error in one specific instance at one specific point in time.

• launchd is the failing component that needs to run always.
• The rest of the information would need to be looked at by an engineer, Typically one employed by Apple, that has a deep understanding of the lowest level of code that runs on the processor.

The next steps for you will depend on how often the error happens and if the machine can start itself up after you power it off.

You could also review these two questions for more details on how to troubleshoot your computer going forward if you wish.

• Understanding kernel panic error log
• How can I troubleshoot Kernel Panics on my iMac

Answer 2

(I'm Not a Mac person, but this applies to many Unices) A kernel panic is basically the Unix equivalent of the modern Windows Blue Screen of Death - an unrecoverable error detected by the kernel, ie the core of the operating system, the part that manages things like processor time, memory, disk access, etc.

This may be caused by a problem affecting the kernel itself (including hardware or (much less likely on Mac than on Windows) driver problems), or by (as in this case) an error causing the init process (in the case of Macs, this is launchd), which is responsible for (directly or indirectly) running all the other processes on your computer, unexpectedly exiting. When this ends, it effectively brings down everything it's started (ie every other process on the system) with it, so the kernel has no option left but to panic.

Hope this helps you understand the general concept, I'm afraid I can't be any more specific as then I'd be going into Mac-specific things with which I'm not familiar.

Answer 3

The answers already given are complete and correct. Since your question may simply boil down to "what is a kernel" and "why did this happen", let me try to explain the jargon.

The software on your computer exists in levels. For instance, there is a part called the windowing system. This is not an application you run, like Safari, but software that is called bySafari in order to draw the window, into which Safari draws webpages. The windowing system, in turn, doesn't talk to the hardware directly, but talks to a lower-level software module that allows it to draw lines on the screen. Anything you do on your computer moves through these kinds of "levels of abstraction" until it gets to the software that talks directly to your hardware.

You kernel is the lowest level of software. It talks directly to your hardware and exposes all the things your computer can do to higher-level processes and modules.

The reason these levels are important is that the higher up something goes wrong, the better your computer deals with it. If you try to open a file that doesn't exist in Safari, Safari will give you a friendly error, which you can use to correct the problem. If something goes wrong in the windowing system, things might start looking funny, or your mouse pointer may suddenly disappear.

A kernel panic happens when something goes wrong in the kernel. As you can guess, the resulting behavior of your computer is the most unfriendly possible. The best you can hope for is that your computer stops in its tracks and prints out a string of obscure looking information, as it did in your case.

Answer 4

As mentioned a kernel panic is when the Operating System (MacOS) crashes. This might be due to a hardware issue which you can largely rule out by running Apple Diagnostics to check your Mac. However it is most likely to be down to some dodgy software on your system so you'll need to investigate - either:

• Top-down: eliminating various software packages (stop running them and/or uninstalling them), till it stops crashing, OR
• Bottom-up: reinstall the MacOS and then slowly reinstalling your software till your see the crash again.