Re: [2.6 patch] i386: always use 4k stacks

[Jeff V. Merkey]

Adrian Bunk wrote:

> On Thu, Dec 15, 2005 at 02:00:13PM -0800, Andrew Morton wrote:
>  
>
> > Adrian Bunk <bunk@xxxxxxxxx> wrote:
> >    
> >
> > > This patch was already sent on:
> > > - 11 Dec 2005
> > > - 5 Dec 2005
> > > - 30 Nov 2005
> > > - 23 Nov 2005
> > > - 14 Nov 2005
> > >      
> > Sigh.  I saw the volume of email last time and though "gee, glad I wasn't
> > cc'ed on that lot".
> >    
>
> If you substract the "this breaks my binary-only M$ Windows driver" 
> emails there's not much volume left.
>
>  
>
> > Supporting 8k stacks is a small amount of code and nobody has seen a need
> > to make changes in there for quite a long time.  So there's little cost to
> > keeping the existing code.
> >
> > And the existing code is useful:
> >
> > a) people can enable it to confirm that their weird crash was due to a
> >   stack overflow.
> >
> > b) If I was going to put together a maximally-stable kernel for a
> >   complex server machine, I'd select 8k stacks.  We're still just too
> >   squeezy, and we've had too many relatively-recent overflows, and there
> >   are still some really deep callpaths in there.
> >    
>
> a1) People turn off 4k stacks and never report the problem / noone 
>    really debugs and fixes the reported problem.
>
> Me threatening people with enabling 4k stacks for everyone already 
> resulted in several fixes.
>
> An how many weird crashes with _different_ causes have you seen?
> It could be that there are only _very_ few problems that noone really 
> debugs brcause disabling 4k stacks fixes the issue.
>  

When you are on the phone with an irrate customer at 2:00 am in the 
morning, and just turning off your broken 4K stack fix
and getting the customer running matters. 4K stacks are a BAD idea. I 
have even found USER SPACE apps
that crash linux without the 8K option. Andrew has spoken. Suck it up 
and deal with it. It's not a problem limited to Windows
drivers.

Jeff

> cu
> Adrian
>
>  

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