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Message-ID: Date: Wed, 9 Nov 2022 11:23:01 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH for-4.17?] x86/paging: return -EINVAL for paging domctls for dying domains Content-Language: en-US To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Cc: Henry.Wang@arm.com, Andrew Cooper , George Dunlap , Wei Liu , =?UTF-8?B?RWR3aW4gVMO2csO2aw==?= , xen-devel@lists.xenproject.org References: <20221108113850.61619-1-roger.pau@citrix.com> <58d5e890-e052-47df-42bb-6cc84aedd4a9@suse.com> <76cde159-088a-3351-56e2-0cf14e9c8116@suse.com> From: Jan Beulich In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: FR0P281CA0118.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:a8::19) To VE1PR04MB6560.eurprd04.prod.outlook.com (2603:10a6:803:122::25) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: VE1PR04MB6560:EE_|DB9PR04MB8235:EE_ X-MS-Office365-Filtering-Correlation-Id: c68cca7f-d6e0-448c-8438-08dac23c6207 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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I guess I'm confused now: This code is called with the domctl lock held, which - as said before - is a questionable thing, for serializing things more than necessary as well as for holding this lock for excessive periods of time. IOW I consider it wrong to depend on that in paging_domctl() to synchronize against domain_kill(). Yet indeed that should eliminate races at present. Jan