Date: Mon, 9 Feb 2015 13:02:27 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>, tglx@linutronix.de,
        mingo@redhat.com, hpa@zytor.com, torvalds@linux-foundation.org,
        konrad.wilk@oracle.com, pbonzini@redhat.com,
        paulmck@linux.vnet.ibm.com, waiman.long@hp.com, davej@redhat.com,
        oleg@redhat.com, x86@kernel.org, paul.gortmaker@windriver.com,
        ak@linux.intel.com, jasowang@redhat.com, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
        xen-devel@lists.xenproject.org, riel@redhat.com,
        borntraeger@de.ibm.com, akpm@linux-foundation.org,
        a.ryabinin@samsung.com, sasha.levin@oracle.com
Subject: Re: [PATCH] x86 spinlock: Fix memory corruption on completing
 completions
Message-ID: <20150209120227.GT21418@twins.programming.kicks-ass.net>
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On Mon, Feb 09, 2015 at 03:04:22PM +0530, Raghavendra K T wrote:
> So we have 3 choices,
> 1. xadd
> 2. continue with current approach.
> 3. a read before unlock and also after that.

For the truly paranoid we have probe_kernel_address(), suppose the lock
was in module space and the module just got unloaded under us.


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