Message-ID: <47BB6558.4020201@zytor.com>
Date: Tue, 19 Feb 2008 15:25:12 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Paul Mackerras <paulus@samba.org>
CC: Ingo Molnar <mingo@elte.hu>, Shi Weihua <shiwh@cn.fujitsu.com>,
       linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
       Roland McGrath <roland@redhat.com>, torvalds@linux-foundation.org
Subject: Re: [PATCH 1/5] signal(x86_32): Improve the signal stack overflow
 check
References: <47B95C4D.6080000@cn.fujitsu.com>	<47BA3CAB.30905@cn.fujitsu.com>	<20080219110536.GA2683@elte.hu> <18363.25743.402510.695150@cargo.ozlabs.ibm.com>
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Paul Mackerras wrote:
> Ingo Molnar writes:
>> * Shi Weihua <shiwh@cn.fujitsu.com> wrote:
>>
>>> We need to check for stack overflow only when the signal is on stack. 
>>> So we can improve the patch "http://lkml.org/lkml/2007/11/27/101" as 
>>> following.
>> thanks, applied.
> 
> These patches change the behaviour of programs that longjmp out of a
> signal handler on an alternate stack, don't they?
> 
> I'm interested to know what gave you confidence that changing that
> behaviour won't break existing working programs.
> 

Shouldn't such programs use sigsetjmp/siglongjmp, which should reset the 
signal stack state?

	-hpa
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