Re: Oops in

From: James Courtier-Dutton
Date: Sat Dec 30 2006 - 13:23:22 EST

Chuck Ebbert wrote:
In-Reply-To: <200612201421.03514.s0348365@xxxxxxxxxxxx>

On Wed, 20 Dec 2006 14:21:03 +0000, Alistair John Strachan wrote:

Any ideas?

BUG: unable to handle kernel NULL pointer dereference at virtual address 00000009

83 ca 10 or $0x10,%edx
3b .byte 0x3b
87 68 01 xchg %ebp,0x1(%eax) <=====
00 00 add %al,(%eax)

Somehow it is trying to execute code in the middle of an instruction.
That almost never works, even when the resulting fragment is a legal
opcode. :)

The real instruction is:

3b 87 68 01 00 00 00 cmp 0x168(%edi),%eax

I'd guess you have some kind of hardware problem. It could also be
a kernel problem where the saved address was corrupted during an
interrupt, but that's not likely.

This looks rather strange.
The times I have seen this sort of problem is:
1) when one bit of the kernel is corrupting another part of it.
2) Kernel modules compiled with different gcc than rest of kernel.
3) kernel headers do not match the kernel being used.

One way to start tracking this down would be to run it with the fewest amount of kernel modules loaded as one can, but still reproduce the problem.

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