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Date: Fri, 18 Sep 2015 14:19:20 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Will Deacon <will.deacon@arm.com>, Oleg Nesterov <oleg@redhat.com>,
        "ebiederm@xmission.com" <ebiederm@xmission.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
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        Andrey Konovalov <andreyknvl@google.com>,
        Alexander Potapenko <glider@google.com>,
        Hans Boehm <hboehm@google.com>
Subject: Re: [PATCH] kernel: fix data race in put_pid
Message-ID: <20150918121920.GE11639@twins.programming.kicks-ass.net>
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On Fri, Sep 18, 2015 at 01:56:37PM +0200, Peter Zijlstra wrote:
> +#ifndef atomic64_read_ctrl
> +static inline int atomic64_read_ctrl(atomic64_t *v)
> +{
> +	int val = atomic64_read(v);

Duh

	long long...

> +	smp_read_barrier_depends(); /* Enforce control dependency. */
> +	return val;
> +}
> +#endif