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User profile for user: Robato
Robato Author
User level: Level 2
439 points

Kernel panic: unaligned frame address

For the experts out there... a kernel panic dessert.

Today's panic happend soon after a cold start, login, and login item startup (Eudora, Safari, iTunes, Terminal, Activity Monitor, Console). The last app that I started manually was TechTools Pro, moved over it with MightyMouse, and voila!

As an extra bonus I add an older "unaligned frame address" panic. I don't recall what I did at that time.

Please give it a serious thought for the next version of the kernel.

*******

Fri Apr 14 21:48:59 2006


Unresolved kernel trap(cpu 0): 0x400 - Inst access DAR=0x00000000023B8010 PC=0x0000000000000000
Latest crash info for cpu 0:
Exception state (sv=0x2D8F2000)
PC=0x00000000; MSR=0x40009030; DAR=0x023B8010; DSISR=0x40000000; LR=0x00000001; R1=0x178BBC20; XCP=0x00000010 (0x400 - Inst access)
Backtrace:
0x00000001
backtrace terminated - unaligned frame address: 0x2820C814

Proceeding back via exception chain:
Exception state (sv=0x2D8F2000)
previously dumped as "Latest" state. skipping...
Exception state (sv=0x2D1DC780)
PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

Kernel version:
Darwin Kernel Version 8.6.0: Tue Mar 7 16:58:48 PST 2006; root:xnu-792.6.70.obj~1/RELEASE_PPC
panic(cpu 0 caller 0xFFFF0004): 0x400 - Inst access
Latest stack backtrace for cpu 0:
Backtrace:
0x00095718 0x00095C30 0x0002683C 0x000A8384 0x000ABD00
Proceeding back via exception chain:
Exception state (sv=0x2D8F2000)
PC=0x00000000; MSR=0x40009030; DAR=0x023B8010; DSISR=0x40000000; LR=0x00000001; R1=0x178BBC20; XCP=0x00000010 (0x400 - Inst access)
Backtrace:
0x00000001
backtrace terminated - unaligned frame address: 0x2820C814

Exception state (sv=0x2D1DC780)
PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

Kernel version:
Darwin Kernel Version 8.6.0: Tue Mar 7 16:58:48 PST 2006; root:xnu-792.6.70.obj~1/RELEASE_PPC

*******

Sat Jan 21 14:18:09 2006


Unresolved kernel trap(cpu 0): 0x400 - Inst access DAR=0x000000000162E006 PC=0x000000004A9F9248
Latest crash info for cpu 0:
Exception state (sv=0x2D822A00)
PC=0x4A9F9248; MSR=0x40009030; DAR=0x0162E006; DSISR=0x40000000; LR=0x4A9F9248; R1=0x17823C20; XCP=0x00000010 (0x400 - Inst access)
Backtrace:
0x4A9F9248
backtrace terminated - unaligned frame address: 0x00000001

Proceeding back via exception chain:
Exception state (sv=0x2D822A00)
previously dumped as "Latest" state. skipping...
Exception state (sv=0x2D1C7000)
PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

Kernel version:
Darwin Kernel Version 8.4.0: Tue Jan 3 18:22:10 PST 2006; root:xnu-792.6.56.obj~1/RELEASE_PPC
panic(cpu 0 caller 0xFFFF0004): 0x400 - Inst access
Latest stack backtrace for cpu 0:
Backtrace:
0x00095718 0x00095C30 0x0002683C 0x000A8384 0x000ABD00
Proceeding back via exception chain:
Exception state (sv=0x2D822A00)
PC=0x4A9F9248; MSR=0x40009030; DAR=0x0162E006; DSISR=0x40000000; LR=0x4A9F9248; R1=0x17823C20; XCP=0x00000010 (0x400 - Inst access)
Backtrace:
0x4A9F9248
backtrace terminated - unaligned frame address: 0x00000001

Exception state (sv=0x2D1C7000)
PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

Kernel version:
Darwin Kernel Version 8.4.0: Tue Jan 3 18:22:10 PST 2006; root:xnu-792.6.56.obj~1/RELEASE_PPC

*******

PowerBook G4 15", 1.67GHz Mac OS X (10.4.6)

Posted on Apr 14, 2006 1:27 PM

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4 replies
User profile for user: Dr. Smoke
Dr. Smoke
User level: Level 9
56,586 points

Apr 14, 2006 1:46 PM in response to Robato

Hi, Robato.

The lines:

Unresolved kernel trap(cpu 0): 0x400 - Inst access

and

panic(cpu 0 caller 0xFFFF0004): 0x400 - Inst access

in your panic log indicates an 0x400 (Instruction Access) panic.

The 0x400 (Instruction access) panic occurs when the processor cannot access the next instruction to be executed.

Potential causes include RAM problems, hard disk corruption, and programming errors. "Programming errors" in this case can include invalid instructions and violations of protected memory, however it is often difficult to differentiate a programming error from a RAM or hard disk problem since the latter two issues can cause a valid instruction to appear invalid. Likewise, this opens the door to the potential for processor errors, i.e. defective processor or other problems with the logic board.

The fact that the Backtrace could not be obtained due to an "unaligned frame address" further complicates interpretation since we cannot tell which, if any, kernel extensions were involved in the panic. This again implies potential RAM problems or a bad address loaded from a swap file on a corrupted hard disk.

See my "Resolving Kernel Panics" FAQ. This FAQ includes step-by-step instructions for identifying and resolving some of the most common causes of kernel panics.

My FAQ is a roadmap: start at the beginning and work through to the end, following the instruction in the order specified, including the "If all else fails..." section if a cause or resolution is not found in an earlier troubleshooting step therein.

Good luck!

😉 Dr. Smoke
Author: Troubleshooting Mac® OS X

---
Note: The information provided in the link(s) above is freely available. However, because I own The X Lab™, a commercial Web site to which some of these links point, the Apple Discussions Terms of Use require I include the following disclosure statement with this post:

I may receive some form of compensation, financial or otherwise, from my recommendation or link.
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User profile for user: Robato
Robato Author
User level: Level 2
439 points

Apr 14, 2006 1:57 PM in response to Dr. Smoke

Dr. Smoke - boy, you are fast!

Thanks for the clarification: so the "Instruction Access" panic is the cause, and "unaligned frame address" just a secondary effect. I will study your "Resolving Kernel Panics" FAQ - thanks for the link.

Since we are talking about unresolved issues, would you mind to have a look at the thread regarding "hfs_relocate: didn't move into metadata zone" and tell us what you think. Many thanks in advance.
http://discussions.apple.com/thread.jspa?threadID=372372&start=0&tstart=0

PowerBook G4 15", 1.67GHz Mac OS X (10.4.6)
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User profile for user: Dr. Smoke
Dr. Smoke
User level: Level 9
56,586 points

Apr 14, 2006 4:06 PM in response to Robato

You wrote:
"Thanks for the clarification: so the "Instruction Access" panic is the cause..."
No. It is the type of panic. That specific type of panic can have multiple causes.

You wrote:
"'unaligned frame address' just a secondary effect"
No. Potentially another symptom.

Re-read my last post. 😉

re: The other issue. You've already marked that as Answered and given away all of the Helpful and Solved points you can, so there's no reason — nor an incentive 😉 — for me to look at it. If the Solved answer didn't solve the problem, then you should not have marked it as Solved.

Good luck!

😉 Dr. Smoke
Author: Troubleshooting Mac® OS X
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User profile for user: Robato
Robato Author
User level: Level 2
439 points

Apr 15, 2006 2:47 AM in response to Robato

For the records: Apple Harware Test did not uncover any hardware problems (20 loops, extended test, test version 2.5).

Dr. Smoke:

You've already marked that as Answered and given away all of the ... points


Sorry for that. Shall I open a new thread? Actually I am serious. The problem looked solved for a while when those msgs started to appear again in system.log. Regarding 'effect' and 'symtom', well, I guess an effect also indicates a cause like a symtom. Anyway.
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Kernel panic: unaligned frame address

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