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Date: Tue, 14 Mar 2017 16:31:47 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Will Deacon <will.deacon@arm.com>, Mark Rutland <mark.rutland@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
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        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>, "x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCH] x86, kasan: add KASAN checks to atomic operations
Message-ID: <20170314153146.GQ5680@worktop>
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On Tue, Mar 14, 2017 at 04:22:52PM +0100, Dmitry Vyukov wrote:
> Any other suggestions?

> -	return i + xadd(&v->counter, i);
> +	return i + arch_xadd(&v->counter, i);

> +#define xadd(ptr, v)					\
> +({							\
> +	__typeof__(ptr) ____ptr = (ptr);		\
> +	kasan_check_write(____ptr, sizeof(*____ptr));	\
> +	arch_xadd(____ptr, (v));			\
> +})

xadd() isn't a generic thing, it only exists inside x86 as a helper to
implement atomic bits.