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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 53EE6C0650F for ; Wed, 14 Aug 2019 08:08:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 29457205C9 for ; Wed, 14 Aug 2019 08:08:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="VVoB/inl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727209AbfHNIIy (ORCPT ); Wed, 14 Aug 2019 04:08:54 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:51958 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725265AbfHNIIx (ORCPT ); Wed, 14 Aug 2019 04:08:53 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x7E88lKd165896; Wed, 14 Aug 2019 08:08:47 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-2019-08-05; bh=jrPcOifHUOUhayzLxc1G1x8+nhLUdUnAVA7EfqZI4zI=; b=VVoB/inlnzSMm+Cveqqbpy5m5Zz16s5QuS4oW8VxwAfLtNyKfsZzKGArD00HCxMSq3Lr fyP1u3GqysMwvz2V7CYXZG7x9U4/ScBSYvMGmMND2rhfqKXzWiTbfa6QwuWfGRwp+boP cbErqv5DX1L1AdrBcSn1W1JkEs4X4Bvpv4HyejGZlW/BCfdNagJmnf/MAbAhqGEtilfb nL1uKPDaRXn0JzvG5Gmg7xb6vriYDITflQCJCfgELmWUbgb3J/RNBpEc7oq46wEHJWBr cUviqERZBrOAIWySKIY+pmKy/GPAIcYCIov4ZLOdDVF4gkwXpk5jE0A1fi0rMuA+iTBg qA== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2120.oracle.com with ESMTP id 2u9pjqk2qu-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 14 Aug 2019 08:08:47 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x7E88gJ1111333; Wed, 14 Aug 2019 08:08:42 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserp3030.oracle.com with ESMTP id 2ubwrgyuu9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 14 Aug 2019 08:08:42 +0000 Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x7E88CKx019282; Wed, 14 Aug 2019 08:08:12 GMT Received: from kadam (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 14 Aug 2019 01:08:01 -0700 Date: Wed, 14 Aug 2019 11:07:54 +0300 From: Dan Carpenter To: Colin King Cc: Jianyun Li , "James E . J . Bottomley" , "Martin K . Petersen" , linux-scsi@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] scsi: mvumi: fix 32 bit shift of a u32 value Message-ID: <20190814080754.GT1974@kadam> References: <20190813180113.14245-1-colin.king@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190813180113.14245-1-colin.king@canonical.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9348 signatures=668684 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908140080 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9348 signatures=668684 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908140080 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 13, 2019 at 07:01:13PM +0100, Colin King wrote: > From: Colin Ian King > > Currently the top 32 bits of a 64 bit address is being calculated > by shifting a u32 twice by 16 bits and then being cast into a 64 > bit address. Shifting a u32 twice by 16 bits always ends up with > a zero. Fix this by casting the u32 to a 64 bit address first > and then shifting it 32 bits. > > Addresses-Coverity: ("Operands don't affect result") > Fixes: f0c568a478f0 ("[SCSI] mvumi: Add Marvell UMI driver") > Signed-off-by: Colin Ian King > --- > drivers/scsi/mvumi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/scsi/mvumi.c b/drivers/scsi/mvumi.c > index 8906aceda4c4..62df69f1e71e 100644 > --- a/drivers/scsi/mvumi.c > +++ b/drivers/scsi/mvumi.c > @@ -296,7 +296,7 @@ static void mvumi_delete_internal_cmd(struct mvumi_hba *mhba, > sgd_getsz(mhba, m_sg, size); > > phy_addr = (dma_addr_t) m_sg->baseaddr_l | > - (dma_addr_t) ((m_sg->baseaddr_h << 16) << 16); > + (dma_addr_t) m_sg->baseaddr_h << 32; Colin, you've sent this patch before on Feb 16, 2019. If you shift by 32 then it's undefined behavior on 32 bit systems. The correct fix is to move the cast which was what your original patch did actually. (((dma_addr_t)m_sg->baseaddr_h << 16) << 16); My suggestion back then was to introduce a macro: /* * The dma_addr_t type can be either 32 or 64 bit. Left shifting a 32 * bit number is undefined so this do two 16 bit left shifts. * */ #define DMA_LSHIFT_32(val) (((dma_addr_t)(val) << 16) << 16) regards, dan carpenter