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 28C6EC33CB2 for ; Fri, 31 Jan 2020 05:00:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E91C520702 for ; Fri, 31 Jan 2020 05:00:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="U46FC8Tz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725268AbgAaFAr (ORCPT ); Fri, 31 Jan 2020 00:00:47 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:39432 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725263AbgAaFAr (ORCPT ); Fri, 31 Jan 2020 00:00:47 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00V4wWVP195240; Fri, 31 Jan 2020 05:00:44 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : mime-version : content-type; s=corp-2019-08-05; bh=/QmMO/8yHL9c5HdMAqWBKY6PNXPxSw2tZWrggSZk29o=; b=U46FC8Tz/eYPUl4MdqZYB+ya38n2vKFUu2I2b1LsuL4eS6qXU4wTf4TM/AP4v2yLl09R 3a0YI8CyKimnydmxv5+JnuNM1KWGR/oHf97TVwM1OQBbuCsYA30OTfRMwA1XwU9DUAem y0LXbZbg0Ft0TojFBH9EY2kkDik9Bt3mWPBEf7mE7BisWgl2eO0f+okv0SO1ocVM5gBo 4hP2A1qO4eNdM6DZwoOKDTGFzXVYRanOmKI2ONe9N7psf1So6RqFoa02oiSF1tiLgg9E MwRq0QhUzzpI/7aLYcEkZSC84W10lEnHinNkoys40LpKb1+o8wjtx3vy6MragCeRPBze hQ== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2130.oracle.com with ESMTP id 2xrd3ur3yq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 31 Jan 2020 05:00:44 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00V4wYPi089524; Fri, 31 Jan 2020 05:00:43 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3020.oracle.com with ESMTP id 2xuheufy9h-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 31 Jan 2020 05:00:43 +0000 Received: from abhmp0010.oracle.com (abhmp0010.oracle.com [141.146.116.16]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 00V50gNL021516; Fri, 31 Jan 2020 05:00:42 GMT Received: from kili.mountain (/129.205.23.165) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 30 Jan 2020 21:00:42 -0800 Date: Fri, 31 Jan 2020 08:00:36 +0300 From: Dan Carpenter To: dave.jiang@intel.com Cc: dmaengine@vger.kernel.org Subject: [bug report] dmaengine: break out channel registration Message-ID: <20200131050036.fqb4ke6phimki4x7@kili.mountain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: NeoMutt/20170113 (1.7.2) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9516 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=771 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001310043 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9516 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=834 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001310043 Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org Hello Dave Jiang, The patch d2fb0a043838: "dmaengine: break out channel registration" from Jan 21, 2020, leads to the following static checker warning: drivers/dma/dmaengine.c:965 __dma_async_device_channel_register() error: potential NULL dereference 'tchan'. drivers/dma/dmaengine.c 954 static int __dma_async_device_channel_register(struct dma_device *device, 955 struct dma_chan *chan, 956 int chan_id) 957 { 958 int rc = 0; 959 int chancnt = device->chancnt; 960 atomic_t *idr_ref; 961 struct dma_chan *tchan; 962 963 tchan = list_first_entry_or_null(&device->channels, ^^^^^^^^ The "or_null" suggests that "tchan" can be NULL 964 struct dma_chan, device_node); 965 if (tchan->dev) { ^^^^^^^^^^ so this should be "if (tchan && tchan->dev)"? 966 idr_ref = tchan->dev->idr_ref; 967 } else { 968 idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL); 969 if (!idr_ref) 970 return -ENOMEM; 971 atomic_set(idr_ref, 0); 972 } 973 974 chan->local = alloc_percpu(typeof(*chan->local)); 975 if (!chan->local) 976 goto err_out; regards, dan carpenter