Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
Message-ID: <501deae6-07a4-1a43-dd52-fc40a409547f@intel.com>
Date:   Thu, 10 Mar 2022 14:15:16 -0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
 Thunderbird/91.6.2
Subject: Re: [PATCH net] ice: Fix race condition during interface enslave
Content-Language: en-US
To:     Jakub Kicinski <kuba@kernel.org>, Ivan Vecera <ivecera@redhat.com>,
        "Jesse Brandeburg" <jesse.brandeburg@intel.com>
CC:     <netdev@vger.kernel.org>, Petr Oros <poros@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        "moderated list:INTEL ETHERNET DRIVERS" 
        <intel-wired-lan@lists.osuosl.org>,
        open list <linux-kernel@vger.kernel.org>
References: <20220310171641.3863659-1-ivecera@redhat.com>
 <20220310135901.39b1abdf@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
From:   Tony Nguyen <anthony.l.nguyen@intel.com>
In-Reply-To: <20220310135901.39b1abdf@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
Content-Type: text/plain; charset="UTF-8"; format=flowed
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?OFRjWnR1NG1LS0kyMTZQS2NhL3VBRUh6NUR6TytOV1FSZjFwZVhodTZuK2NB?=
 =?utf-8?B?M2hxMHBjYmxXcUtua1pGakJOUXIyVHJQMkJXYnBrUFE1OGFqTXpkbGN4aS9F?=
 =?utf-8?B?cHNFS0RPcHJKZDZPdklQSXZ0bHE1TlBpWnBwNlpUWWF3ay9BWWR0VC9KWXNQ?=
 =?utf-8?B?R21mWmZPcUdhclNYMzhsY3ZpajdweVVuYlFMR2hVTTRiS1loUzduQmsxdWEw?=
 =?utf-8?B?Yk40SnJJL204RE1sWDZ2eWJ0ZVVFVXM1MlZ1cEUxQmEwY0pZRFpMdTUxQjNm?=
 =?utf-8?B?enZmVElTd0E4dmpOTkd2Rk8zOEV6cytOZzlzblBLSVJEREVYQkxlTDJYdkZW?=
 =?utf-8?B?UTFNcmdFQmNjNEw3RHVHRzVtMnZEMFhEWlRFUEVhNWVWZnhsenprY2MzYVBp?=
 =?utf-8?B?dFZyWVJGVVJ6UTh1bVVKUVA5VDgyY2tVZUFFb0lodUpiSzVvWjBQNm5DT3pZ?=
 =?utf-8?B?TEd5bmw2MmRqZ2trVEk0ZHczY3NZcTM4bHQ1b3l0QnVwSVF0NlRsd0R5N0k2?=
 =?utf-8?B?YVRidHdHelJnQkVFSitlNVROV1h6TmVra05JZVMwdzZlWWhWaDVMNG5uM2Ew?=
 =?utf-8?B?WG10emJabEU0K2hiaDFkcmY1QkdxUU5ReG02TDJxOHdZd2FzbmNmM1NLeVNJ?=
 =?utf-8?B?Ym5TcE5GUlJBSHdhSUtaQXNUZll5SGZLVllKTDZTZDBnNUVwL3RxMU1pVStk?=
 =?utf-8?B?SmlTbUYzSFFtaXU4RHJjS254blczQXFPRUdueFdIeStrNkM5SktrUC9nV01x?=
 =?utf-8?B?VmxWUURZTk0zNXd0MC85N2hpWmE0NERERGdwbk54N1djZVBGZ0FRRXpTMHZN?=
 =?utf-8?B?Y3JFZTlYQVdEM1ZxWkl3NDQvU0F6eHVZeDFXL1hHZ2dkVk9QV0dIL1pIUGVu?=
 =?utf-8?B?TDZJNHlCWm1mNEJjUWlMb3pLdk0yY3dtNU5YME03Ylo1ek9pVGJIUWEwUk9R?=
 =?utf-8?B?NTk2cGpMcGdaU1RLOWtIUVhPUmJrY2V1VjdNR0FTK28vTHVDOVRUaThiWXE5?=
 =?utf-8?B?dnAxVHFLVEgwbU0yZDBCaXQ2cy9TdGJvNU1GSnRPRXhPRTBmcGpiczk0SUkz?=
 =?utf-8?B?YWp2TjRGR3lxVzVIQ05OSDh3YXRIRlpTL0FtOHZFNkFrZm5mM2g0Wmg0R3lo?=
 =?utf-8?B?WVVjRVYzK04wQys2QmF5dnFhd0NjbTZsSU03V2oyd1hYZ2dYSnFDK3A0dk4r?=
 =?utf-8?B?ZUZPSEszeVc5UVQ3RkpwOHJmUTl3Tm1PTFAwV20vN3EwT29rK0JmR3owU3Zl?=
 =?utf-8?B?VUcwc0MxUHY5cTJHYWt4YWt1dGxtU0xzdVJGWDN3aHBQR0V4bjBqZ1paK0R3?=
 =?utf-8?B?WUhlZUxTSTRnNTIvTTNzS3BubG9rZ0I0RnFpSktvQ0V3ellJdXR4R2JXMzlU?=
 =?utf-8?B?YUpVZ2ZRWHdVVTFWM0dOVWw1L2htazZHSmFvZy9NbXZGV242VUFUTkpTOFk4?=
 =?utf-8?B?MzBNQi9ESlBWVW90Qy95UHpNS09OVkk5RDhaaUpYYnIyRmlYVlRmdWs2dVRM?=
 =?utf-8?B?dHFIUDF5K293LzRENEMwUnRWa3EyakNuQ0tTNVhUYmY5T1FWVFVERW9iRGJh?=
 =?utf-8?B?RU8wclpseGd5dVF4bTBGMDlnWGlnZDc2ZFR6K1V4Q2JtOC9HeVo3a2wvd3ZP?=
 =?utf-8?B?N3FIbXY0UGh4YlNjTlRQVVJRb2wzOHY0dWxOVDR2QTgyLzN3VE9ZelJKN3Z0?=
 =?utf-8?B?YWljNE8vWS9zdzFGV3lQNUs1VFhGTUdZd3kycWNBeGNOTzA2Y04yTFFteEtq?=
 =?utf-8?B?d3kzazNkN1BCTHh2MHR1SFVWNnlzUGVvMTlVSk9tQVYyVVF5aXdCT3VRdEo0?=
 =?utf-8?B?WFRiRnhNbGljbnlFdGk5Z21kM2srUmh2QnI1NWprd0lqakR1eGt5dG15dDNO?=
 =?utf-8?B?QTRBd2pEVlFBc1RQRFNWTExsWVZFY1A0U2tvekg1a20yc2hCVzFVZFRJb09X?=
 =?utf-8?B?dEVoTmJ1NzRrbWM5ZDhabWNVenpIS0RIQ0RSNjg0czRuYitvdkxuZHJjd0N6?=
 =?utf-8?B?RWtQTHpuckJBPT0=?=
X-MS-Exchange-CrossTenant-Network-Message-Id: d6734f51-19f6-4fa8-8508-08da02e37728
X-MS-Exchange-CrossTenant-AuthSource: SN6PR11MB3229.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Mar 2022 22:15:20.8197
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: wvqadLV/9k8KJ+eXAm+weV/A2kv9UhLPhKduOYu5a2+MHGWdDhhg3EvBgY1Sixi98hgcmzZHqAGt6Tm1eNDmFMMHwRx73/0QRjJ99/kjx3Q=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR11MB4170
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
	DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,NICE_REPLY_A,RDNS_NONE,SPF_HELO_NONE,
	T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no
	version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
	lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


On 3/10/2022 1:59 PM, Jakub Kicinski wrote:
> On Thu, 10 Mar 2022 18:16:41 +0100 Ivan Vecera wrote:
>> Commit 5dbbbd01cbba83 ("ice: Avoid RTNL lock when re-creating
>> auxiliary device") changes a process of re-creation of aux device
>> so ice_plug_aux_dev() is called from ice_service_task() context.
>> This unfortunately opens a race window that can result in dead-lock
>> when interface has left LAG and immediately enters LAG again.
>>
>> Reproducer:
>> ```
>> #!/bin/sh
>>
>> ip link add lag0 type bond mode 1 miimon 100
>> ip link set lag0
>>
>> for n in {1..10}; do
>>          echo Cycle: $n
>>          ip link set ens7f0 master lag0
>>          sleep 1
>>          ip link set ens7f0 nomaster
>> done
> What's the priority on this one? The loop max of 10 seems a little
> worrying.
>
> Tony, Jesse, is it important enough to push into 5.17 or do you prefer
> to take it via the normal path and do full QA? The blamed patch come
> in to 5.17-rc it seems.

Hi Jakub,

Yea, it'd be preferred to make it into 5.17. Feel free to take it directly.

Thanks,

Tony