Re: linux-2.6 x86_64 kgdb issue
From: Andi Kleen
Date: Wed May 31 2006 - 05:40:56 EST
> My bet is that in this case I was storing a LOT of
> data in the thread structure, so the space left for
> the stack was massively reduced.
Ok so it was your bug. Don't do that.
> Sure but the debugger environment must tolerate larger stacks.
No, Linux doesn't tolerate larger stacks.
> But this can miss a minor abuse. The interrupt check
> is a quick and simple hack but I wonder if it's really
> optimal for commercial implementations.
In practice if you overwrite thread_info you crash eventually
and it's noticed. If you write below thread_info but keep
ti intact then the redzone would likely not catch it either.
I don't think an additional red zone would improve overflow detection
in a significant way.
> I think all modules should be ABLE to be built in.
If you have a working module it can be easily built in too.
Just hacks that don't work with modules are bad.
-Andi
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