From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751782Ab2ILTUf (ORCPT ); Wed, 12 Sep 2012 15:20:35 -0400 Received: from caiajhbdcbbj.dreamhost.com ([208.97.132.119]:49673 "EHLO homiemail-a7.g.dreamhost.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751160Ab2ILTUd (ORCPT ); Wed, 12 Sep 2012 15:20:33 -0400 Message-ID: <1347477630.3384.1.camel@offbook> Subject: Re: [PATCH v2] lib: gcd: prevent possible div by 0 From: Davidlohr Bueso Reply-To: dave@gnu.org To: Andrew Morton Cc: Eric Dumazet , lkml , stable@vger.kernel.org Date: Wed, 12 Sep 2012 21:20:30 +0200 In-Reply-To: <20120912121055.bd417043.akpm@linux-foundation.org> References: <1347287719.2561.14.camel@offbook> <20120912121055.bd417043.akpm@linux-foundation.org> Organization: GNU Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2012-09-12 at 12:10 -0700, Andrew Morton wrote: > On Mon, 10 Sep 2012 16:35:19 +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 > > Why cc:stable? If this patch fixes some known problem in the current > kernel then that really really should have been described in the > changelog. Always. Please. Ok, I will keep it in mind next time. No known problem (at least that I know of), but due to the nature of the potential bug, I thought that it was worth adding it to stable. Thanks. > > > ... > > --- 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; > > -- > > 1.7.9.5 > > > > >