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Date: Fri, 27 Feb 2015 10:06:13 +0000
From: Will Deacon <will.deacon@arm.com>
To: Pranith Kumar <bobby.prani@gmail.com>
Cc: Catalin Marinas <Catalin.Marinas@arm.com>,
        Steve Capper <steve.capper@linaro.org>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH] ARM64: cmpxchg.h: Clear the exclusive access bit on
 fail
Message-ID: <20150227100612.GB3628@arm.com>
References: <1425016026-19766-1-git-send-email-bobby.prani@gmail.com>
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On Fri, Feb 27, 2015 at 05:46:55AM +0000, Pranith Kumar wrote:
> In cmpxchg(), we do a load exclusive on an address and upon a comparison fail,
> we skip the store exclusive instruction. This can result in the exclusive bit
> still set. If there was a store exclusive after this to the same address, that
> will see the exclusive bit set. This should not happen.

... and the problem with that is?

> We need to clear the exclusive bit in these cases.

Why?

Will