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, 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 8B5FCC433DF for ; Wed, 17 Jun 2020 17:18:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B96521527 for ; Wed, 17 Jun 2020 17:18:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="WkhgoKnE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726981AbgFQRSO (ORCPT ); Wed, 17 Jun 2020 13:18:14 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:34902 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726597AbgFQRSN (ORCPT ); Wed, 17 Jun 2020 13:18:13 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 05HHHmcZ103922; Wed, 17 Jun 2020 17:17:59 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 : in-reply-to; s=corp-2020-01-29; bh=9VQqTPZpR0kzjjfzvsdc4Cd29YvF0dcmDmbQ6puPfZE=; b=WkhgoKnEal4c9PClFZzLziJhMWKcbyIeQUkNxg7Qso6eH8O9emFNz5Yxyn80BZRLSz6q +YgycPyZ+vfek55tD//ARjQCfv9w2jKX0ln7oZX06tsBb7B1pfRCTtLxs4Ova+2nhHxd ukCTajQ4fUmm4HjcdFXx0OK1NUiK8w7UBM97bjqI8coEjQM+bMlEBIaJge8yY5pLDNwB gpBp8atNBQgx818Es5Bagq/yfskFLGaS/F9sHbA+G3aSiCbG7a+XkfOKaOUKBO9Mx1PO 1cNgg2RPzBTk2TXBhe7JW4fAiqXYeptpaqcVA5skwU61al7p/63LNcan8tHYeuDtnGyy XQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 31q65yvmda-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 17 Jun 2020 17:17:59 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 05HHDADm140357; Wed, 17 Jun 2020 17:15:58 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserp3030.oracle.com with ESMTP id 31q66netxq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 Jun 2020 17:15:58 +0000 Received: from abhmp0006.oracle.com (abhmp0006.oracle.com [141.146.116.12]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 05HHFuNR021623; Wed, 17 Jun 2020 17:15:57 GMT Received: from kadam (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 17 Jun 2020 10:15:56 -0700 Date: Wed, 17 Jun 2020 20:15:50 +0300 From: Dan Carpenter To: Mike Leach Cc: Mathieu Poirier , Suzuki K Poulose , Alexander Shishkin , Greg Kroah-Hartman , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH v2] coresight: cti: Fix error handling in probe Message-ID: <20200617171549.GA9686@kadam> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9655 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 adultscore=0 phishscore=0 mlxscore=0 bulkscore=0 malwarescore=0 mlxlogscore=999 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006170136 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9655 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 lowpriorityscore=0 malwarescore=0 bulkscore=0 phishscore=0 adultscore=0 priorityscore=1501 mlxscore=0 spamscore=0 clxscore=1015 mlxlogscore=999 suspectscore=0 impostorscore=0 cotscore=-2147483648 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006170137 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There were a couple problems with error handling in the probe function: 1) If the "drvdata" allocation failed then it lead to a NULL dereference. 2) On several error paths we decremented "nr_cti_cpu" before it was incremented which lead to a reference counting bug. There were also some parts of the error handling which were not bugs but were messy. The error handling was confusing to read. It printed some unnecessary error messages. The simplest way to fix these problems was to create a cti_pm_setup() function that did all the power management setup in one go. That way when we call cti_pm_release() we don't have to deal with the complications of a partially configured power management config. I reversed the "if (drvdata->ctidev.cpu >= 0)" condition in cti_pm_release() so that it mirros the new cti_pm_setup() function. Fixes: 6a0953ce7de9 ("coresight: cti: Add CPU idle pm notifer to CTI devices") Signed-off-by: Dan Carpenter --- v2: I accidentally introduced a bug in cti_pm_release() in v1. drivers/hwtracing/coresight/coresight-cti.c | 96 ++++++++++++--------- 1 file changed, 54 insertions(+), 42 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c index 40387d58c8e7..d2da5bf9f552 100644 --- a/drivers/hwtracing/coresight/coresight-cti.c +++ b/drivers/hwtracing/coresight/coresight-cti.c @@ -747,17 +747,50 @@ static int cti_dying_cpu(unsigned int cpu) return 0; } +static int cti_pm_setup(struct cti_drvdata *drvdata) +{ + int ret; + + if (drvdata->ctidev.cpu == -1) + return 0; + + if (nr_cti_cpu) + goto done; + + cpus_read_lock(); + ret = cpuhp_setup_state_nocalls_cpuslocked( + CPUHP_AP_ARM_CORESIGHT_CTI_STARTING, + "arm/coresight_cti:starting", + cti_starting_cpu, cti_dying_cpu); + if (ret) { + cpus_read_unlock(); + return ret; + } + + ret = cpu_pm_register_notifier(&cti_cpu_pm_nb); + cpus_read_unlock(); + if (ret) { + cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_CTI_STARTING); + return ret; + } + +done: + nr_cti_cpu++; + cti_cpu_drvdata[drvdata->ctidev.cpu] = drvdata; + + return 0; +} + /* release PM registrations */ static void cti_pm_release(struct cti_drvdata *drvdata) { - if (drvdata->ctidev.cpu >= 0) { - if (--nr_cti_cpu == 0) { - cpu_pm_unregister_notifier(&cti_cpu_pm_nb); + if (drvdata->ctidev.cpu == -1) + return; - cpuhp_remove_state_nocalls( - CPUHP_AP_ARM_CORESIGHT_CTI_STARTING); - } - cti_cpu_drvdata[drvdata->ctidev.cpu] = NULL; + cti_cpu_drvdata[drvdata->ctidev.cpu] = NULL; + if (--nr_cti_cpu == 0) { + cpu_pm_unregister_notifier(&cti_cpu_pm_nb); + cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_CTI_STARTING); } } @@ -823,19 +856,14 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id) /* driver data*/ drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL); - if (!drvdata) { - ret = -ENOMEM; - dev_info(dev, "%s, mem err\n", __func__); - goto err_out; - } + if (!drvdata) + return -ENOMEM; /* Validity for the resource is already checked by the AMBA core */ base = devm_ioremap_resource(dev, res); - if (IS_ERR(base)) { - ret = PTR_ERR(base); - dev_err(dev, "%s, remap err\n", __func__); - goto err_out; - } + if (IS_ERR(base)) + return PTR_ERR(base); + drvdata->base = base; dev_set_drvdata(dev, drvdata); @@ -854,8 +882,7 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id) pdata = coresight_cti_get_platform_data(dev); if (IS_ERR(pdata)) { dev_err(dev, "coresight_cti_get_platform_data err\n"); - ret = PTR_ERR(pdata); - goto err_out; + return PTR_ERR(pdata); } /* default to powered - could change on PM notifications */ @@ -867,35 +894,20 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id) drvdata->ctidev.cpu); else cti_desc.name = coresight_alloc_device_name(&cti_sys_devs, dev); - if (!cti_desc.name) { - ret = -ENOMEM; - goto err_out; - } + if (!cti_desc.name) + return -ENOMEM; /* setup CPU power management handling for CPU bound CTI devices. */ - if (drvdata->ctidev.cpu >= 0) { - cti_cpu_drvdata[drvdata->ctidev.cpu] = drvdata; - if (!nr_cti_cpu++) { - cpus_read_lock(); - ret = cpuhp_setup_state_nocalls_cpuslocked( - CPUHP_AP_ARM_CORESIGHT_CTI_STARTING, - "arm/coresight_cti:starting", - cti_starting_cpu, cti_dying_cpu); - - if (!ret) - ret = cpu_pm_register_notifier(&cti_cpu_pm_nb); - cpus_read_unlock(); - if (ret) - goto err_out; - } - } + ret = cti_pm_setup(drvdata); + if (ret) + return ret; /* create dynamic attributes for connections */ ret = cti_create_cons_sysfs(dev, drvdata); if (ret) { dev_err(dev, "%s: create dynamic sysfs entries failed\n", cti_desc.name); - goto err_out; + goto pm_release; } /* set up coresight component description */ @@ -908,7 +920,7 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id) drvdata->csdev = coresight_register(&cti_desc); if (IS_ERR(drvdata->csdev)) { ret = PTR_ERR(drvdata->csdev); - goto err_out; + goto pm_release; } /* add to list of CTI devices */ @@ -927,7 +939,7 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id) dev_info(&drvdata->csdev->dev, "CTI initialized\n"); return 0; -err_out: +pm_release: cti_pm_release(drvdata); return ret; } -- 2.27.0