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

Jeff V. Merkey
2005-12-15T22:36:55Z

Adrian Bunk wrote:

>On Thu, Dec 15, 2005 at 02:00:13PM -0800, Andrew Morton wrote:
>
>
>>Adrian Bunk <bunk@stusta.de> 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
>
>
>