From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5D40C43387 for ; Wed, 16 Jan 2019 08:51:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8B45720866 for ; Wed, 16 Jan 2019 08:51:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="PDiFxS7Z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390306AbfAPIvS (ORCPT ); Wed, 16 Jan 2019 03:51:18 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:41456 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388743AbfAPIvS (ORCPT ); Wed, 16 Jan 2019 03:51:18 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id x0G8nGnG157669; Wed, 16 Jan 2019 08:51:07 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=cYT1XohZQGkO4yk5AtVj8Z3RinnutoeyYKFNnwSkSL4=; b=PDiFxS7ZU/bI2W2geEShQj0HwvINYTUtLM8qu5RsvkwS71Aq3mINTDppvX1M9aWik25w h/PaK29q5BD2s/TFoqQ7i3Iod6d/bZUNC5LWhKeCtvJQYqCFtkWSoTsp+Y6YNDZQm2vG WBi4qvh7TF6xE4DWMNGKwNEoS4XDYXW0KPFjpE7X/hEhGRNlQVklTgX0Ug83x/Wy3Y7r Y/RKY2QLHnBOomJOFcCJs57PRAnMuzKh25nT81Tr3UAjmxOc3uGQj6KfPiLl50VFhFSi vv6Um8OSlHyj9mQ0ZaoLeDcRbXyLu09WwgHF4mL7Es7UakOt1xUATg/gIMjbyIxnNFLW fg== Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by userp2130.oracle.com with ESMTP id 2pybkcgfm3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 16 Jan 2019 08:51:07 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id x0G8p6eV031322 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 16 Jan 2019 08:51:07 GMT Received: from abhmp0005.oracle.com (abhmp0005.oracle.com [141.146.116.11]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x0G8p65d010925; Wed, 16 Jan 2019 08:51:06 GMT Received: from kadam (/10.175.54.137) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 16 Jan 2019 00:51:05 -0800 Date: Wed, 16 Jan 2019 11:50:51 +0300 From: Dan Carpenter To: Colin King Cc: Chas Williams <3chas3@gmail.com>, linux-atm-general@lists.sourceforge.net, netdev@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] atm: he: fix sign-extension overflow on large shift Message-ID: <20190116085051.GC4482@kadam> References: <20190115180338.32357-1-colin.king@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190115180338.32357-1-colin.king@canonical.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9137 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=641 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901160075 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Jan 15, 2019 at 06:03:38PM +0000, Colin King wrote: > From: Colin Ian King > > Shifting the 1 by exp by an int can lead to sign-extension overlow when > exp is 31 since 1 is an signed int and sign-extending this result to an > unsigned long long will set the upper 32 bits. Fix this by shifting an > unsigned long. You could just cast it to unsigned. rate_cps = (unsigned long long) (1U << exp) * (man + 512) >> 9; I don't think it makes a difference at runtime because we just pick buf = 4 either way... regards, dan carpenter