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 E5105CD68E6 for ; Wed, 11 Oct 2023 08:37:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230413AbjJKIh4 (ORCPT ); Wed, 11 Oct 2023 04:37:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45498 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229957AbjJKIhz (ORCPT ); Wed, 11 Oct 2023 04:37:55 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D642A4 for ; Wed, 11 Oct 2023 01:37:52 -0700 (PDT) Received: from kwepemm000007.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4S55dt2kC0zLqJ0; Wed, 11 Oct 2023 16:33:54 +0800 (CST) Received: from [192.168.98.200] (10.67.165.2) by kwepemm000007.china.huawei.com (7.193.23.189) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Wed, 11 Oct 2023 16:37:49 +0800 Message-ID: <9579f762-24ce-0826-dc7b-2c79c969f192@huawei.com> Date: Wed, 11 Oct 2023 16:37:49 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird CC: , , , , , , Subject: Re: [PATCH drivers/perf: hisi:] drivers/perf: hisi: fix NULL pointer issue when uninstall hns3 pmu driver To: Yicong Yang , , , , References: <20231009105038.126040-1-shaojijie@huawei.com> <504cc838-d587-8bd0-601e-85f11b69c72b@huawei.com> From: Jijie Shao In-Reply-To: <504cc838-d587-8bd0-601e-85f11b69c72b@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.67.165.2] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemm000007.china.huawei.com (7.193.23.189) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org on 2023/10/10 17:32, Yicong Yang wrote: > Hi Jijie, > > On 2023/10/9 18:50, Jijie Shao wrote: >> From: Hao Chen >> >> When uninstall hns3 pmu driver, it will call cpuhp_state_remove_instance() >> and then callback function hns3_pmu_offline_cpu() is called, it may cause >> NULL pointer call trace when other driver is installing or uninstalling >> concurrently. >> > More information about the calltrace you've met and how to reproduce this? > I'm not sure why other drivers are involved. > >> As John Garry's opinion, cpuhp_state_remove_instance() is used for shared >> interrupt, and using cpuhp_state_remove_instance_nocalls() is fine for PCIe >> or HNS3 pmu. >> > I'm a bit confused here. We need to update the using CPU and migrate the perf > context as well as the interrupt affinity in cpuhp::teardown() callback, so > it make sense to not call this on driver detachment. But I cannot figure > out why this is related to the shared interrupt, more details? > ok，I will send v2 to add more details. Thanks