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Message-ID: <1347476706.2526.3.camel@offbook>
Subject: Re: [PATCH v2] lib: gcd: prevent possible div by 0
From: Davidlohr Bueso <dave@gnu.org>
Reply-To: dave@gnu.org
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        lkml <linux-kernel@vger.kernel.org>, stable@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Wed, 12 Sep 2012 21:05:06 +0200
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References: <1347287719.2561.14.camel@offbook>
Organization: GNU
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ping? Cc'ing Greg for stable.

On Mon, 2012-09-10 at 16:35 +0200, Davidlohr Bueso wrote:
> Account for all properties when a and/or b are 0:
> gcd(0, 0) = 0
> gcd(a, 0) = a
> gcd(0, b) = b
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Davidlohr Bueso <dave@gnu.org>
> ---
> V2: simplified checking with b = 0 (Eric)
> 
>  lib/gcd.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/lib/gcd.c b/lib/gcd.c
> index cce4f3c..3657f12 100644
> --- a/lib/gcd.c
> +++ b/lib/gcd.c
> @@ -9,6 +9,9 @@ unsigned long gcd(unsigned long a, unsigned long b)
>  
>  	if (a < b)
>  		swap(a, b);
> +
> +	if (!b)
> +		return a;
>  	while ((r = a % b) != 0) {
>  		a = b;
>  		b = r;