Re: 2.6.0-test9-mm3

[Linus Torvalds <torvalds@osdl.org>]

On Fri, 14 Nov 2003, Martin J. Bligh wrote:
> 
> Linus had some debug thing for triple faults, a few months ago, IIRC ...
> probably in the archives somewhere ...

Triple faults you can't debug, they raise a line outside the CPU, and 
normal PC hardware will cause that to just trigger a reboot.

But double faults do get caught, and that debugging stuff actually is in
the standard kernel. It won't give _nearly_ as good a debug report as a
"normal" oops, since I didn't want the double-fault handler to touch
anything even remotely unsafe, but it often gives a good hint about what
might be wrong. Certainly better than triple-faulting did (which we still
do for _catastrophic_ corruption, eg totally munged kernel page tables etc
- it's just very hard to avoid once you get corrupted enough).

		Linus

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