From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Date: Fri, 17 Apr 2020 10:24:20 +0000 Subject: Re: [bug report] bus: mhi: core: Add support for data transfer Message-Id: <20200417102420.GR1163@kadam> List-Id: References: <20200407135559.GA109574@mwanda> <20200407143304.GH2442@Mani-XPS-13-9360> <20200417101428.GA10295@Mani-XPS-13-9360> In-Reply-To: <20200417101428.GA10295@Mani-XPS-13-9360> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Manivannan Sadhasivam Cc: Hemant Kumar , linux-arm-msm@vger.kernel.org, kernel-janitors@vger.kernel.org On Fri, Apr 17, 2020 at 03:44:28PM +0530, Manivannan Sadhasivam wrote: > Hi Hemant, > > On Thu, Apr 16, 2020 at 08:37:16PM -0700, Hemant Kumar wrote: > > > > On 4/7/20 7:33 AM, Manivannan Sadhasivam wrote: > > > Hi Dan, > > > > > > On Tue, Apr 07, 2020 at 04:55:59PM +0300, Dan Carpenter wrote: > > > > Hello Manivannan Sadhasivam, > > > > > > > > The patch 189ff97cca53: "bus: mhi: core: Add support for data > > > > transfer" from Feb 20, 2020, leads to the following static checker > > > > warning: > > > > > > > > drivers/bus/mhi/core/main.c:1153 mhi_queue_buf() > > > > error: double locked 'mhi_chan->lock' (orig line 1110) > > > > > > > > drivers/bus/mhi/core/main.c > > > > 1142 } > > > > 1143 > > > > 1144 /* Toggle wake to exit out of M2 */ > > > > 1145 mhi_cntrl->wake_toggle(mhi_cntrl); > > > > 1146 > > > > 1147 if (mhi_chan->dir = DMA_TO_DEVICE) > > > > 1148 atomic_inc(&mhi_cntrl->pending_pkts); > > > > 1149 > > > > 1150 if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl))) { > > > > 1151 unsigned long flags; > > > > 1152 > > > > 1153 read_lock_irqsave(&mhi_chan->lock, flags); > > > > parse_xfer_event is taking read lock : read_lock_bh(&mhi_chan->lock); first > > and later > > > > mhi_queue_buf takes read lock: read_lock_irqsave(&mhi_chan->lock, flags); > > > > Both are read locks which are recursive, is this problematic ? > > > > read_locks are recursive but I wanted to make the static checker happy. Don't do things just to make the static checker happy. regards, dan carpenter 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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=no 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 72355C352BE for ; Fri, 17 Apr 2020 10:24:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E90721D95 for ; Fri, 17 Apr 2020 10:24:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="ML+VRCiA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729256AbgDQKYf (ORCPT ); Fri, 17 Apr 2020 06:24:35 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:33730 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726207AbgDQKYf (ORCPT ); Fri, 17 Apr 2020 06:24:35 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 03HAOIUK144895; Fri, 17 Apr 2020 10:24:31 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-2020-01-29; bh=MLO25+uu0p1lJymH6NFPaGxDp70jIn+676ep69GijtY=; b=ML+VRCiAPW6O4RJ9+mw3z4cV+yo+IkuCjjm2nmF7rW3uBvSDQFmzzAWhfCt0yrcgNHiR xp/40Qa78iZECt3yOT/UYOxFzwOnfjXFv3lAjANPhZKGgyuEpeJ1hU18J4c5S7PSwq+Q VggjoB1hfzqV8/8PnmzB85psTYVeshzsiFAqpDPlEnAzfRWfhDbOYCzzIWAJpyOzA+NO JHzIiRvmaNXIbjISABgikDIcU9GgXc5p1QyOsuUaACf0FmaDX5tEuJVOGx2wpuwstjlP ogvciNFi8xR78R+6uFecobRrAKI8S6e9xzeBxYu4AgHDCNpsUFmBQlIJ/90P86oPo2Ps kQ== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2120.oracle.com with ESMTP id 30emejp5ex-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 17 Apr 2020 10:24:31 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 03HAMBEi131502; Fri, 17 Apr 2020 10:24:31 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3020.oracle.com with ESMTP id 30dn9jjn8p-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 17 Apr 2020 10:24:30 +0000 Received: from abhmp0011.oracle.com (abhmp0011.oracle.com [141.146.116.17]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 03HAOT7W011924; Fri, 17 Apr 2020 10:24:29 GMT Received: from kadam (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 17 Apr 2020 03:24:28 -0700 Date: Fri, 17 Apr 2020 13:24:20 +0300 From: Dan Carpenter To: Manivannan Sadhasivam Cc: Hemant Kumar , linux-arm-msm@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [bug report] bus: mhi: core: Add support for data transfer Message-ID: <20200417102420.GR1163@kadam> References: <20200407135559.GA109574@mwanda> <20200407143304.GH2442@Mani-XPS-13-9360> <20200417101428.GA10295@Mani-XPS-13-9360> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200417101428.GA10295@Mani-XPS-13-9360> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9593 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 mlxscore=0 adultscore=0 spamscore=0 phishscore=0 bulkscore=0 suspectscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004170082 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9593 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 impostorscore=0 mlxscore=0 suspectscore=0 lowpriorityscore=0 spamscore=0 mlxlogscore=999 bulkscore=0 adultscore=0 phishscore=0 clxscore=1015 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004170082 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Fri, Apr 17, 2020 at 03:44:28PM +0530, Manivannan Sadhasivam wrote: > Hi Hemant, > > On Thu, Apr 16, 2020 at 08:37:16PM -0700, Hemant Kumar wrote: > > > > On 4/7/20 7:33 AM, Manivannan Sadhasivam wrote: > > > Hi Dan, > > > > > > On Tue, Apr 07, 2020 at 04:55:59PM +0300, Dan Carpenter wrote: > > > > Hello Manivannan Sadhasivam, > > > > > > > > The patch 189ff97cca53: "bus: mhi: core: Add support for data > > > > transfer" from Feb 20, 2020, leads to the following static checker > > > > warning: > > > > > > > > drivers/bus/mhi/core/main.c:1153 mhi_queue_buf() > > > > error: double locked 'mhi_chan->lock' (orig line 1110) > > > > > > > > drivers/bus/mhi/core/main.c > > > > 1142 } > > > > 1143 > > > > 1144 /* Toggle wake to exit out of M2 */ > > > > 1145 mhi_cntrl->wake_toggle(mhi_cntrl); > > > > 1146 > > > > 1147 if (mhi_chan->dir == DMA_TO_DEVICE) > > > > 1148 atomic_inc(&mhi_cntrl->pending_pkts); > > > > 1149 > > > > 1150 if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl))) { > > > > 1151 unsigned long flags; > > > > 1152 > > > > 1153 read_lock_irqsave(&mhi_chan->lock, flags); > > > > parse_xfer_event is taking read lock : read_lock_bh(&mhi_chan->lock); first > > and later > > > > mhi_queue_buf takes read lock: read_lock_irqsave(&mhi_chan->lock, flags); > > > > Both are read locks which are recursive, is this problematic ? > > > > read_locks are recursive but I wanted to make the static checker happy. Don't do things just to make the static checker happy. regards, dan carpenter