From patchwork Wed Dec 21 18:21:23 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 9483619 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id D2908600C1 for ; Wed, 21 Dec 2016 18:26:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C9B4E28458 for ; Wed, 21 Dec 2016 18:26:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BE1CB2847B; Wed, 21 Dec 2016 18:26:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 4FD5B28458 for ; Wed, 21 Dec 2016 18:26:31 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1cJlZB-000809-4C; Wed, 21 Dec 2016 18:24:41 +0000 Received: from galois.linutronix.de ([2a01:7a0:2:106d:700::1]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1cJlZ6-0007wa-ML for linux-arm-kernel@lists.infradead.org; Wed, 21 Dec 2016 18:24:38 +0000 Received: from localhost ([127.0.0.1]) by Galois.linutronix.de with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1cJlYE-0007kd-Rv; Wed, 21 Dec 2016 19:23:43 +0100 Date: Wed, 21 Dec 2016 19:21:23 +0100 (CET) From: Thomas Gleixner To: LKML Subject: ARM: imx: mmdc: Fix completely broken cpu hotplug code Message-ID: User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20161221_102436_930298_1C834846 X-CRM114-Status: GOOD ( 18.20 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Shawn Guo , Sebastian Sewior , Frank Li , Zhengyu Shen , LAK Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP The cpu hotplug support of this perf driver is broken in several ways: 1) It adds a instance before setting up the state. 2) The state for the instance is different from the state of the callback. It's just a randomly chosen state. 3) The instance registration is not error checked so nobody noticed that the call can never succeed. 4) The state for the multi install callbacks is chosen randomly and overwrites existing state. This is now prevented by the core code so the call is guaranteed to fail. 5) The error exit path in the init function leaves the instance registered and then frees the memory which contains the enqueued hlist node. 6) The remove function is removing the state and not the instance. Fix it by: - Setting up the state before adding instances. Use a dynamically allocated state for it. - Install instances after the state has been set up - Remove the instance in the error path before freeing memory - Remove instance not the state in the driver remove callback While at is use raw_cpu_processor_id(), because cpu_processor_id() cannot be used in preemptible context, and set the driver data after successful registration of the pmu. Fixes: e76bdfd7403a ("ARM: imx: Added perf functionality to mmdc driver") Signed-off-by: Thomas Gleixner Cc: Zhengyu Shen Cc: Frank Li Cc: Shawn Guo Acked-by: Shawn Guo --- arch/arm/mach-imx/mmdc.c | 34 ++++++++++++++++++++++------------ include/linux/cpuhotplug.h | 1 + 2 files changed, 23 insertions(+), 12 deletions(-) --- a/arch/arm/mach-imx/mmdc.c +++ b/arch/arm/mach-imx/mmdc.c @@ -60,6 +60,7 @@ #define to_mmdc_pmu(p) container_of(p, struct mmdc_pmu, pmu) +static enum cpuhp_state cpuhp_mmdc_state; static int ddr_type; struct fsl_mmdc_devtype_data { @@ -451,8 +452,8 @@ static int imx_mmdc_remove(struct platfo { struct mmdc_pmu *pmu_mmdc = platform_get_drvdata(pdev); + cpuhp_state_remove_instance_nocalls(cpuhp_mmdc_state, &pmu_mmdc->node); perf_pmu_unregister(&pmu_mmdc->pmu); - cpuhp_remove_state_nocalls(CPUHP_ONLINE); kfree(pmu_mmdc); return 0; } @@ -472,6 +473,18 @@ static int imx_mmdc_perf_init(struct pla return -ENOMEM; } + /* The first instance registers the hotplug state */ + if (!cpuhp_mmdc_state) { + ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, + "perf/arm/mmdc:online", NULL, + mmdc_pmu_offline_cpu); + if (ret < 0) { + pr_err("cpuhp_setup_state_multi failed\n"); + goto pmu_free; + } + cpuhp_mmdc_state = ret; + } + mmdc_num = mmdc_pmu_init(pmu_mmdc, mmdc_base, &pdev->dev); if (mmdc_num == 0) name = "mmdc"; @@ -485,26 +498,23 @@ static int imx_mmdc_perf_init(struct pla HRTIMER_MODE_REL); pmu_mmdc->hrtimer.function = mmdc_pmu_timer_handler; - cpuhp_state_add_instance_nocalls(CPUHP_ONLINE, - &pmu_mmdc->node); - cpumask_set_cpu(smp_processor_id(), &pmu_mmdc->cpu); - ret = cpuhp_setup_state_multi(CPUHP_AP_NOTIFY_ONLINE, - "MMDC_ONLINE", NULL, - mmdc_pmu_offline_cpu); - if (ret) { - pr_err("cpuhp_setup_state_multi failure\n"); - goto pmu_register_err; - } + cpumask_set_cpu(raw_smp_processor_id(), &pmu_mmdc->cpu); + + /* Register the pmu instance for cpu hotplug */ + cpuhp_state_add_instance_nocalls(cpuhp_mmdc_state, &pmu_mmdc->node); ret = perf_pmu_register(&(pmu_mmdc->pmu), name, -1); - platform_set_drvdata(pdev, pmu_mmdc); if (ret) goto pmu_register_err; + + platform_set_drvdata(pdev, pmu_mmdc); return 0; pmu_register_err: pr_warn("MMDC Perf PMU failed (%d), disabled\n", ret); + cpuhp_state_remove_instance_nocalls(cpuhp_mmdc_state, &pmu_mmdc->node); hrtimer_cancel(&pmu_mmdc->hrtimer); +pmu_free: kfree(pmu_mmdc); return ret; } --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -140,6 +140,7 @@ enum cpuhp_state { CPUHP_AP_PERF_ARM_CCI_ONLINE, CPUHP_AP_PERF_ARM_CCN_ONLINE, CPUHP_AP_PERF_ARM_L2X0_ONLINE, + CPUHP_AP_PERF_ARM_MMDC_ONLINE, CPUHP_AP_WORKQUEUE_ONLINE, CPUHP_AP_RCUTREE_ONLINE, CPUHP_AP_NOTIFY_ONLINE,