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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55B72C761A6 for ; Mon, 3 Apr 2023 11:09:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232128AbjDCLJK (ORCPT ); Mon, 3 Apr 2023 07:09:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60022 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232118AbjDCLJG (ORCPT ); Mon, 3 Apr 2023 07:09:06 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58F9412071 for ; Mon, 3 Apr 2023 04:09:00 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Pqp4m4llGz6J6lN; Mon, 3 Apr 2023 19:07:04 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Mon, 3 Apr 2023 12:08:57 +0100 Date: Mon, 3 Apr 2023 12:08:56 +0100 From: Jonathan Cameron To: Junhao He CC: , , , , , , , , , , Subject: Re: [PATCH 2/2] drivers/perf: hisi: add NULL check for name Message-ID: <20230403120856.000027d7@Huawei.com> In-Reply-To: <20230403081423.62460-3-hejunhao3@huawei.com> References: <20230403081423.62460-1-hejunhao3@huawei.com> <20230403081423.62460-3-hejunhao3@huawei.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500002.china.huawei.com (7.191.160.78) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 3 Apr 2023 16:14:23 +0800 Junhao He wrote: > When allocations fails that can be NULL now. > > If the name provided is NULL, then the initialization process of the PMU > type and dev will be skipped in function perf_pmu_register(). > Consequently, the PMU will not be able to register into the kernel. > Moreover, in the case of unregister the PMU, the function device_del() > will need to handle NULL pointers, which potentially can cause issues. If you could be more specific in what the problem is wrt to a NULL pointer here that would be great. Given there is code to skip the device registration without it being an error, I'd expect the release flow to be safe in that condition. Seems like a sensible change even without that. So with some more info feel free to add Reviewed-by: Jonathan Cameron > > So move this allocation above the cpuhp_state_add_instance() and directly > return if it does fail. > > Signed-off-by: Junhao He > --- > drivers/perf/hisilicon/hisi_uncore_ddrc_pmu.c | 17 ++++++++++------- > drivers/perf/hisilicon/hisi_uncore_hha_pmu.c | 7 +++++-- > drivers/perf/hisilicon/hisi_uncore_l3c_pmu.c | 11 +++++------ > 3 files changed, 20 insertions(+), 15 deletions(-) > > diff --git a/drivers/perf/hisilicon/hisi_uncore_ddrc_pmu.c b/drivers/perf/hisilicon/hisi_uncore_ddrc_pmu.c > index 8a3d74ddcd6d..ffb039d05d07 100644 > --- a/drivers/perf/hisilicon/hisi_uncore_ddrc_pmu.c > +++ b/drivers/perf/hisilicon/hisi_uncore_ddrc_pmu.c > @@ -499,13 +499,6 @@ static int hisi_ddrc_pmu_probe(struct platform_device *pdev) > if (ret) > return ret; > > - ret = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_HISI_DDRC_ONLINE, > - &ddrc_pmu->node); > - if (ret) { > - dev_err(&pdev->dev, "Error %d registering hotplug;\n", ret); > - return ret; > - } > - > if (ddrc_pmu->identifier >= HISI_PMU_V2) > name = devm_kasprintf(&pdev->dev, GFP_KERNEL, > "hisi_sccl%u_ddrc%u_%u", > @@ -516,6 +509,16 @@ static int hisi_ddrc_pmu_probe(struct platform_device *pdev) > "hisi_sccl%u_ddrc%u", ddrc_pmu->sccl_id, > ddrc_pmu->index_id); > > + if (!name) > + return -ENOMEM; > + > + ret = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_HISI_DDRC_ONLINE, > + &ddrc_pmu->node); > + if (ret) { > + dev_err(&pdev->dev, "Error %d registering hotplug;\n", ret); > + return ret; > + } > + > hisi_pmu_init(ddrc_pmu, THIS_MODULE); > > ret = perf_pmu_register(&ddrc_pmu->pmu, name, -1); > diff --git a/drivers/perf/hisilicon/hisi_uncore_hha_pmu.c b/drivers/perf/hisilicon/hisi_uncore_hha_pmu.c > index 5701a84edb0e..15caf99e1eef 100644 > --- a/drivers/perf/hisilicon/hisi_uncore_hha_pmu.c > +++ b/drivers/perf/hisilicon/hisi_uncore_hha_pmu.c > @@ -510,6 +510,11 @@ static int hisi_hha_pmu_probe(struct platform_device *pdev) > if (ret) > return ret; > > + name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "hisi_sccl%u_hha%u", > + hha_pmu->sccl_id, hha_pmu->index_id); > + if (!name) > + return -ENOMEM; > + > ret = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_HISI_HHA_ONLINE, > &hha_pmu->node); > if (ret) { > @@ -517,8 +522,6 @@ static int hisi_hha_pmu_probe(struct platform_device *pdev) > return ret; > } > > - name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "hisi_sccl%u_hha%u", > - hha_pmu->sccl_id, hha_pmu->index_id); > hisi_pmu_init(hha_pmu, THIS_MODULE); > > ret = perf_pmu_register(&hha_pmu->pmu, name, -1); > diff --git a/drivers/perf/hisilicon/hisi_uncore_l3c_pmu.c b/drivers/perf/hisilicon/hisi_uncore_l3c_pmu.c > index 68596b566344..794dbcd19b7a 100644 > --- a/drivers/perf/hisilicon/hisi_uncore_l3c_pmu.c > +++ b/drivers/perf/hisilicon/hisi_uncore_l3c_pmu.c > @@ -544,6 +544,11 @@ static int hisi_l3c_pmu_probe(struct platform_device *pdev) > if (ret) > return ret; > > + name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "hisi_sccl%u_l3c%u", > + l3c_pmu->sccl_id, l3c_pmu->ccl_id); > + if (!name) > + return -ENOMEM; > + > ret = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_HISI_L3_ONLINE, > &l3c_pmu->node); > if (ret) { > @@ -551,12 +556,6 @@ static int hisi_l3c_pmu_probe(struct platform_device *pdev) > return ret; > } > > - /* > - * CCL_ID is used to identify the L3C in the same SCCL which was > - * used _UID by mistake. > - */ > - name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "hisi_sccl%u_l3c%u", > - l3c_pmu->sccl_id, l3c_pmu->ccl_id); > hisi_pmu_init(l3c_pmu, THIS_MODULE); > > ret = perf_pmu_register(&l3c_pmu->pmu, name, -1);