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Fri, 12 Jun 2020 13:46:32 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 05CDebgZ089950; Fri, 12 Jun 2020 13:46:31 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3020.oracle.com with ESMTP id 31masr049h-177 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 12 Jun 2020 13:46:31 +0000 Received: from abhmp0001.oracle.com (abhmp0001.oracle.com [141.146.116.7]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 05CCBfU3014972; Fri, 12 Jun 2020 12:11:41 GMT Received: from mwanda (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 12 Jun 2020 05:11:40 -0700 Date: Fri, 12 Jun 2020 15:11:33 +0300 From: Dan Carpenter To: Mike Leach Subject: [PATCH] coresight: cti: Fix error handling in probe Message-ID: <20200612121133.GA1139533@mwanda> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200612121047.GF4282@kadam> X-Mailer: git-send-email haha only kidding X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9649 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 malwarescore=0 mlxscore=0 spamscore=0 mlxlogscore=999 suspectscore=0 bulkscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006120101 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9649 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 impostorscore=0 cotscore=-2147483648 priorityscore=1501 spamscore=0 suspectscore=0 lowpriorityscore=0 bulkscore=0 mlxlogscore=999 malwarescore=0 mlxscore=0 phishscore=0 clxscore=1011 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006120102 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200612_064643_303744_A35670E3 X-CRM114-Status: GOOD ( 22.58 ) X-Spam-Score: -2.5 (--) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-2.5 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [156.151.31.86 listed in list.dnswl.org] -0.0 SPF_HELO_PASS SPF: HELO matches SPF record -0.0 SPF_PASS SPF: sender matches SPF record -0.0 RCVD_IN_MSPIKE_H2 RBL: Average reputation (+2) [156.151.31.86 listed in wl.mailspike.net] -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid 0.0 UNPARSEABLE_RELAY Informational: message has unparseable relay lines -0.0 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mathieu Poirier , Suzuki K Poulose , Alexander Shishkin , Greg Kroah-Hartman , kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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 --- Please note!!! I cannot compile this patch. Mike can you review it? 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] = drvdata; + 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; }