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Mon, 9 Mar 2026 20:29:00 +0000 Date: Mon, 9 Mar 2026 15:32:42 -0500 From: Ira Weiny To: Sungwoo Kim , Davidlohr Bueso , Jonathan Cameron , Dave Jiang , Alison Schofield , "Vishal Verma" , Ira Weiny , "Dan Williams" , Ben Widawsky CC: , Sungwoo Kim , Jonathan Cameron , , Subject: Re: [PATCH] cxl/region: Fix a race bug in delete_region_store Message-ID: <69af2e6a81cf6_1a62c11004c@iweiny-mobl.notmuch> References: <20260308185958.2453707-2-iam@sung-woo.kim> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20260308185958.2453707-2-iam@sung-woo.kim> X-ClientProxiedBy: SJ0PR13CA0220.namprd13.prod.outlook.com (2603:10b6:a03:2c1::15) To PH3PPF9E162731D.namprd11.prod.outlook.com (2603:10b6:518:1::d3c) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH3PPF9E162731D:EE_|PH8PR11MB7072:EE_ X-MS-Office365-Filtering-Correlation-Id: 9ec4dde9-9c0c-4b47-3675-08de7e1a7f6b X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|366016|7053199007; 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Both calls succeed in cxl_find_region_by_name() > (which only does device_find_child_by_name and takes a reference), and > both then proceed to call devm_release_action(). The first call atomically > removes and releases the devres entry successfully. The second call finds > no matching entry, causing devres_release() to return -ENOENT, which trips > the WARN_ON. > > Fix this by replacing devm_release_action() with devm_remove_action_nowarn() > followed by a manual call to unregister_region(). devm_remove_action_nowarn() > removes the devres tracking entry and returns an error code. > [snip] > > Fixes: 779dd20cfb56 ("cxl/region: Add region creation support") > Signed-off-by: Sungwoo Kim Reviewed-by: Ira Weiny [snip]