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Date: Tue, 08 Nov 2011 16:34:28 +0900
From: HAYASAKA Mitsuo <mitsuo.hayasaka.hu@hitachi.com>
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To: Pekka Enberg <penberg@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Randy Dunlap <rdunlap@xenotime.net>,
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Subject: Re: [RFC PATCH 0/5] x86: check stack overflows more reliably
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Hi Pekka,

Thank you for your comments.

(2011/11/07 16:00), Pekka Enberg wrote:
> On Mon, Nov 7, 2011 at 7:51 AM, Mitsuo Hayasaka
> <mitsuo.hayasaka.hu@hitachi.com> wrote:
>> (2) check stack overflow in detail
>>    Currently, only kernel stack is checked for the overflow,
>>    which is not sufficient for enterprise systems. To enhance
>>    reliability, expand stack overflow checking to IRQ and
>>    exception stacks optionally. This is disabled by default
>>    in Kconfig.
> 
> This sounds useful. What's the reason for not enabling this by
> default? Performance regressions?

I'm worried about performance regressions because this patch checks 
a stack overflow in detail.

However, I guess there is no problem for enabling it by default 
since this option is for debug and appears only if a DEBUG_STACKOVERFLOW
option is enabled.

So, I'd like to send the revised patch if it does not have any further problem.


>                         Pekka
> 
>