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Subject: Re: [PATCH 1/5] signal(x86_32): Improve the signal stack overflow
	check
From: Harvey Harrison <harvey.harrison@gmail.com>
To: Roland McGrath <roland@redhat.com>
Cc: Shi Weihua <shiwh@cn.fujitsu.com>, Ingo Molnar <mingo@elte.hu>,
       linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
       "H. Peter Anvin" <hpa@zytor.com>
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Date: Tue, 19 Feb 2008 21:54:07 -0800
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On Tue, 2008-02-19 at 18:49 -0800, Roland McGrath wrote:
> > I spent some time read you mail carefully and dig into the code again.
> > 
> > And yes, you are right. It's possible that SA_ONSTACK has been cleared
> > before the second signal on the same stack comes.
> 
> It's not necessary for SA_ONSTACK to have "been cleared", by which I assume
> you mean a sigaction call with SA_ONSTACK not set in sa_flags.  That is
> indeed possible, but it's not the only case your patch broke.  It can just
> be a different signal whose sigaction never had SA_ONSTACK, when you are
> still on the signal stack from an earlier signal that did have SA_ONSTACK.
> 
> > So this patch is wrong  :( . I will revise the other 4 patches.
> 
> For 2 and 3, I would rather just wait until we unify signal.c anyway.
> 

I've been looking at that, at the same time a bunch of ia32/signal.c
looks like it can go away.

Harvey

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