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 34116C7EE29 for ; Thu, 8 Jun 2023 13:14:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236110AbjFHNOq (ORCPT ); Thu, 8 Jun 2023 09:14:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231626AbjFHNOp (ORCPT ); Thu, 8 Jun 2023 09:14:45 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07BD2210C; Thu, 8 Jun 2023 06:14:43 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4QcPl90XYPz6802G; Thu, 8 Jun 2023 21:12:37 +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; Thu, 8 Jun 2023 14:14:41 +0100 Date: Thu, 8 Jun 2023 14:14:40 +0100 From: Jonathan Cameron To: Junhao He CC: , , , , , , , , Subject: Re: [PATCH] drivers/perf: hisi: Don't migrate perf to the CPU going to teardown Message-ID: <20230608141440.000003db@Huawei.com> In-Reply-To: <20230608114326.27649-1-hejunhao3@huawei.com> References: <20230608114326.27649-1-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: lhrpeml100005.china.huawei.com (7.191.160.25) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Thu, 8 Jun 2023 19:43:26 +0800 Junhao He wrote: > The driver needs to migrate the perf context if the current using CPU going > to teardown. By the time calling the cpuhp::teardown() callback the > cpu_online_mask() hasn't updated yet and still includes the CPU going to > teardown. In current driver's implementation we may migrate the context > to the teardown CPU and leads to the below calltrace: > > ... > [ 368.104662][ T932] task:cpuhp/0 state:D stack: 0 pid: 15 ppid: 2 flags:0x00000008 > [ 368.113699][ T932] Call trace: > [ 368.116834][ T932] __switch_to+0x7c/0xbc > [ 368.120924][ T932] __schedule+0x338/0x6f0 > [ 368.125098][ T932] schedule+0x50/0xe0 > [ 368.128926][ T932] schedule_preempt_disabled+0x18/0x24 > [ 368.134229][ T932] __mutex_lock.constprop.0+0x1d4/0x5dc > [ 368.139617][ T932] __mutex_lock_slowpath+0x1c/0x30 > [ 368.144573][ T932] mutex_lock+0x50/0x60 > [ 368.148579][ T932] perf_pmu_migrate_context+0x84/0x2b0 > [ 368.153884][ T932] hisi_pcie_pmu_offline_cpu+0x90/0xe0 [hisi_pcie_pmu] > [ 368.160579][ T932] cpuhp_invoke_callback+0x2a0/0x650 > [ 368.165707][ T932] cpuhp_thread_fun+0xe4/0x190 > [ 368.170316][ T932] smpboot_thread_fn+0x15c/0x1a0 > [ 368.175099][ T932] kthread+0x108/0x13c > [ 368.179012][ T932] ret_from_fork+0x10/0x18 > ... > > Use function cpumask_any_but() to find one correct active cpu to fixes > this issue. > > Fixes: 8404b0fbc7fb ("drivers/perf: hisi: Add driver for HiSilicon PCIe PMU") > Signed-off-by: Junhao He Reviewed-by: Jonathan Cameron > --- > drivers/perf/hisilicon/hisi_pcie_pmu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/perf/hisilicon/hisi_pcie_pmu.c b/drivers/perf/hisilicon/hisi_pcie_pmu.c > index 0bc8dc36aff5..14f8b4b03337 100644 > --- a/drivers/perf/hisilicon/hisi_pcie_pmu.c > +++ b/drivers/perf/hisilicon/hisi_pcie_pmu.c > @@ -683,7 +683,7 @@ static int hisi_pcie_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node) > > pcie_pmu->on_cpu = -1; > /* Choose a new CPU from all online cpus. */ > - target = cpumask_first(cpu_online_mask); > + target = cpumask_any_but(cpu_online_mask, cpu); > if (target >= nr_cpu_ids) { > pci_err(pcie_pmu->pdev, "There is no CPU to set\n"); > return 0;