Messages in this thread | | | Date | Thu, 17 Nov 2011 11:59:39 -0500 | From | Jason Baron <> | Subject | Re: [RFC PATCH 0/5] x86: check stack overflows more reliably |
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On Tue, Nov 08, 2011 at 04:34:28PM +0900, HAYASAKA Mitsuo wrote: > 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. > >
Another thought might be to make stack_overflow_check() depend on a jump label. Its not something that going to be switch on/off often, and then perhaps we wouldn't even need DEBUG_STACKOVERFLOW...It seems like a good use-case to me.
Thanks,
-Jason
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