From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756546AbcARTM7 (ORCPT ); Mon, 18 Jan 2016 14:12:59 -0500 Received: from shards.monkeyblade.net ([149.20.54.216]:41984 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756491AbcARTM4 (ORCPT ); Mon, 18 Jan 2016 14:12:56 -0500 Date: Mon, 18 Jan 2016 14:12:53 -0500 (EST) Message-Id: <20160118.141253.803019327755668580.davem@davemloft.net> To: dan.carpenter@oracle.com Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [patch] ide: silence some underflow warnings From: David Miller In-Reply-To: <20151113143401.GC1445@mwanda> References: <20151113143401.GC1445@mwanda> X-Mailer: Mew version 6.6 on Emacs 24.5 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 18 Jan 2016 11:12:55 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dan Carpenter Date: Fri, 13 Nov 2015 17:34:01 +0300 > Back in the day we used to just say this code was root only so it was > ok that the bounds checking was sloppy. These days it annoys static > checkers so we fix it. > > In the original code "c > INT_MAX" was never true since "c" was an int. > I am not sure what was intended so I left it alone. But because I made > "c" unsigned it means we don't have a warning any more. > > The second warning is that we cap "i" but allow negatives leading to an > underflow of the ide_disks_chs[] array. The third set of warnings is > because these values come from the user and we cap most of the upper > bounds but allow negative values. Negative cylinders doesn't make > sense. > > drivers/ide/ide.c:262 ide_set_disk_chs() warn: impossible condition '(c > ((~0 >> 1))) => (s32min-s32max > s32max)' > drivers/ide/ide.c:270 ide_set_disk_chs() warn: check 'ide_disks_chs[i]' for negative offsets 'i' = s32min. extra = 's32min-19' > drivers/ide/ide.c:271 ide_set_disk_chs() warn: no lower bound on 'h' > > Signed-off-by: Dan Carpenter Applied.