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Date: Wed, 4 May 2016 08:32:33 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
        Borislav Petkov <bp@alien8.de>, Stas Sergeev <stsp@list.ru>,
        Al Viro <viro@zeniv.linux.org.uk>, Aleksa Sarai <cyphar@cyphar.com>,
        "Amanieu d'Antras" <amanieu@gmail.com>,
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        Andrew Morton <akpm@linux-foundation.org>,
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        "H. Peter Anvin" <hpa@zytor.com>,
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        Peter Zijlstra <peterz@infradead.org>,
        Richard Weinberger <richard@nod.at>,
        Sasha Levin <sasha.levin@oracle.com>,
        Shuah Khan <shuahkh@osg.samsung.com>, Tejun Heo <tj@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vladimir Davydov <vdavydov@parallels.com>, linux-api@vger.kernel.org
Subject: Re: [PATCH 1/4] signals/sigaltstack: If SS_AUTODISARM, bypass
 on_sig_stack
Message-ID: <20160504063233.GB9499@gmail.com>
References: <cover.1462296606.git.luto@kernel.org>
 <c46bee4654ca9e68c498462fd11746e2bd0d98c8.1462296606.git.luto@kernel.org>
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* Andy Lutomirski <luto@kernel.org> wrote:

> If a signal stack is set up with SS_AUTODISARM, then the kernel
> inherently avoids incorrectly resetting the signal stack if signals
> recurse: the signal stack will be reset on the first signal
> delivery.  This means that we don't need check the stack pointer
> when delivering signals if SS_AUTODISARM is set.
> 
> This will make segmented x86 programs more robust: currently there's
> a hole that could be triggered if ESP/RSP appears to point to the
> signal stack but actually doesn't due to a nonzero SS base.
> 
> Signed-off-by: Stas Sergeev <stsp@list.ru>

Presuably that SOB from Stas is stray, as there's no matching From: line?
I've removed it.

Thanks,

	Ingo