Re: Wanted: simple, safe x86 stack overflow detection

[Hugh Dickins]

On Tue, 6 Mar 2007, Chuck Ebbert wrote:
> 
> In the 4k/4k stack i386 kernel, is there any fundamental reason it
> can't be 4k/8k? We seem to be mostly hitting problems in overflowing
> the IRQ stack... I think. Overhead would only be 4k per CPU for that.

For all of history prior to 2.6.20, there's been the fundamental
reason that even interrupt stacks need to access current_thread_info,
and that involved the (THREAD_SIZE - 1) mask.  But 2.6.20's read_pda
using %gs gets away from that: my guess is that it's now possible
for i386 to use different sized stacks.

Hugh
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