Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Dexuan Cui <decui@microsoft.com>
To:     Long Li <longli@microsoft.com>,
        "longli@linuxonhyperv.com" <longli@linuxonhyperv.com>,
        KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Rob Herring <robh@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [Patch v2 1/2] PCI: hv: Fix a race condition when removing the
 device
Thread-Topic: [Patch v2 1/2] PCI: hv: Fix a race condition when removing the
 device
Thread-Index: AQHXNzrEqHm1W7VddEiGdCJpDqqWbKrBrccwgADBxQCAAAH5cA==
Date:   Fri, 23 Apr 2021 18:41:32 +0000
Message-ID: <MW2PR2101MB0892D7E83CC44D97F4317871BF459@MW2PR2101MB0892.namprd21.prod.outlook.com>
References: <1619070346-21557-1-git-send-email-longli@linuxonhyperv.com>
 <MW2PR2101MB0892A9A0972199A2FF6D68B0BF459@MW2PR2101MB0892.namprd21.prod.outlook.com>
 <BYAPR21MB1271F9B76FAA423D7BE6DDEECE459@BYAPR21MB1271.namprd21.prod.outlook.com>
In-Reply-To: <BYAPR21MB1271F9B76FAA423D7BE6DDEECE459@BYAPR21MB1271.namprd21.prod.outlook.com>
Accept-Language: en-US
Content-Language: en-US
msip_labels: MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_ActionId=825368ff-303b-448a-ba43-6f3872c68267;MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_ContentBits=0;MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Enabled=true;MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Method=Standard;MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Name=Internal;MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_SetDate=2021-04-23T06:58:52Z;MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_SiteId=72f988bf-86f1-41af-91ab-2d7cd011db47;
authentication-results: microsoft.com; dkim=none (message not signed)
 header.d=none;microsoft.com; dmarc=none action=none
 header.from=microsoft.com;
x-originating-ip: [2601:600:8b00:6b90:55f8:4d3d:9b51:7264]
x-ms-publictraffictype: Email
x-ms-office365-filtering-correlation-id: d2c5a49f-cf4d-4370-e446-08d906876a74
x-ms-traffictypediagnostic: MWHPR2101MB0809:
x-ms-exchange-transport-forked: True
x-microsoft-antispam-prvs: <MWHPR2101MB080907708B0DD33D8D5F2E0CBF459@MWHPR2101MB0809.namprd21.prod.outlook.com>
x-ms-oob-tlc-oobclassifiers: OLM:6790;
x-ms-exchange-senderadcheck: 1
x-microsoft-antispam: BCL:0;
x-microsoft-antispam-message-info: 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
x-forefront-antispam-report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:MW2PR2101MB0892.namprd21.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(366004)(66946007)(82950400001)(921005)(8936002)(66446008)(8676002)(64756008)(110136005)(2906002)(66476007)(76116006)(5660300002)(7696005)(66556008)(86362001)(52536014)(83380400001)(38100700002)(6506007)(186003)(71200400001)(33656002)(55016002)(10290500003)(9686003)(82960400001)(316002)(8990500004)(4744005)(122000001)(478600001);DIR:OUT;SFP:1102;
x-ms-exchange-antispam-messagedata: =?us-ascii?Q?f/EBjZgz5xAz1+xAghAIQqTewsnEsh2RvEJ4uGBB2kFIqAdpmfyZSsim+j7x?=
 =?us-ascii?Q?sjhT7OeHGfqJn3oGCZkh3WHZZbOvSvDV9jdjtxpmOWuGmm8ZF7mkLMnWVvXA?=
 =?us-ascii?Q?89U32ooVrO9t650akl0vp40HtRDxKp8iEwAn00FJ8Hf1x9G74glo6wxHBV/7?=
 =?us-ascii?Q?REyBcWb3CCkxACZWl1FqU6QG/VuEwX6/vwXOBUsU9s2fNp45eeig0ij97PPG?=
 =?us-ascii?Q?hLCVVLyxrMHE3zdGHg8dn8RkyD+CnlZRTF9/Asi73gmWV2XAi/cI7sCCgFc4?=
 =?us-ascii?Q?gvkbSfOnMQv0mMN3wejbRZ4n0sVvk8HYYfHkOeDnxANQBKtjtf6x2wAhrrHC?=
 =?us-ascii?Q?fFYOJKaX0omxUUSZRcGhn3sQc0ts9x+oZ7/DFYe8on9adka1vws4RDhSztQh?=
 =?us-ascii?Q?5skK9ymD2Jgfh85Wy3N2y+GR4QlUsOKgQ7lLyjZepZSzlbYPhkSUBOzpKhQ4?=
 =?us-ascii?Q?nSidaoDYAl4uZ3/KJ4EvxUmLY8gPnqo8qDEw6xX8aBpFLWXDWID1IKuGJw/o?=
 =?us-ascii?Q?7WzOAcpiPbPNPLYI8Tar+8s0ZhOfb73afHLWQDr4ZT9TabvIsXUrH3pwxZdP?=
 =?us-ascii?Q?k89g/sCJ0nvdHvC0sboUCpy9W2lgly6McwQhjknWhBxDwk1lDe5jWBksBnWJ?=
 =?us-ascii?Q?TM1jzvBgCoWhimKJMyluxRkmkHBSEGZk1hlS8nErlvWZE86VKw9gP7Izo1CB?=
 =?us-ascii?Q?pd4qjJqFXv3uQfvD+n93rsAjUdVli79dBvupS/cnvKUfV+P0ofr4YSo/l5J4?=
 =?us-ascii?Q?/k7C9WeYsbwl2SUEYHyTbh7i89zA3/nJO8hoiduy6uazKsVJBlHoihhz6QbH?=
 =?us-ascii?Q?G67pXnUmCsQthg5jpxmbPqd9SwVrLT/N3CxBXRsHldJs0qBRcnoSKf0D3rkb?=
 =?us-ascii?Q?ZQlCZeGrjmEcQpj2I3RZvcpLya5MYrz/Tba3U0cvuw4cG+PUa6GLE1Kj06ht?=
 =?us-ascii?Q?w+C9aZA97pieEEGcPnfA5yto/roMuscEAW0sgZ0RxMGQ2Xub+Go7f0ALZnvF?=
 =?us-ascii?Q?XJEuYIgLZgfyAdC2GvzD7a9SZGBkaYKsH+DlnB8n3jR8Ig+B/jCL6BM5bP7C?=
 =?us-ascii?Q?jyPMS3Fg0mXpZgR7Nj/4PSulnyBjygVrPbgaKT7R6Vd+XDnvpTccNGn/Etqr?=
 =?us-ascii?Q?Sb7Q6q6Kj+MyW0XqE4WJDHgry9KzWNB1oUTTkNQrbYfjCkvDNNSN8LbrbaUt?=
 =?us-ascii?Q?+Gd2JMlyLxrwhAkGr7gWHDe5HwrqqYE/hKRBL+TPOZm2HkXfS/Z0Ya5PNtR5?=
 =?us-ascii?Q?EKDoulwnWV16mQCV8ltN6vxMSbhn5bOkHJt6QyX0AKge/py/LNdrsVr21o3f?=
 =?us-ascii?Q?i5HUgFjA/6LvF4Dnrppm7yfm6NRDy9f8DA6gKo2tCf+E0AmkDo8RfPJJkL9x?=
 =?us-ascii?Q?zSgDTRQZuVGeWF0dGNKjpR2GEY2j?=
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginatorOrg: microsoft.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: MW2PR2101MB0892.namprd21.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: d2c5a49f-cf4d-4370-e446-08d906876a74
X-MS-Exchange-CrossTenant-originalarrivaltime: 23 Apr 2021 18:41:32.4783
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: eNhzXhz8kRBJyUqHI9r6z945oobe6nfyXtzbeO5C+ctIsY0/5IhFqvtw3cknBkCWSk5C1kHMYi6aQGSYRgnYzA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR2101MB0809
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

> From: Long Li <longli@microsoft.com>
> Sent: Friday, April 23, 2021 11:32 AM
> > ...
> > If we test "rmmod pci-hyperv", I suspect the warning will be printed:
> > hv_pci_remove() -> hv_pci_bus_exit() -> hv_pci_start_relations_work():
>=20
> In most case, it will not print anything.

If I read the code correctly, I think the warning is printed _every time_ w=
e
unload pci-hyperv.

> It will print something if there is a PCI_BUS_RELATION work pending at th=
e time
> of remove. The same goes to PCI_EJECT. In those cases, the message is val=
uable
> to troubleshooting.