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Tue, 10 Mar 2026 21:34:37 +0000 Date: Tue, 10 Mar 2026 14:34:29 -0700 From: Alison Schofield To: Li Ming CC: Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Davidlohr Bueso , Jonathan Cameron , "Dave Jiang" , Vishal Verma , "Ira Weiny" , Dan Williams , "Bjorn Helgaas" , Ben Cheatham , , , Subject: Re: [PATCH 2/7] cxl/memdev: Hold memdev lock during memdev poison injection/clear Message-ID: References: <20260310-fix_access_endpoint_without_drv_check-v1-0-94fe919a0b87@zohomail.com> <20260310-fix_access_endpoint_without_drv_check-v1-2-94fe919a0b87@zohomail.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20260310-fix_access_endpoint_without_drv_check-v1-2-94fe919a0b87@zohomail.com> X-ClientProxiedBy: BYAPR01CA0058.prod.exchangelabs.com (2603:10b6:a03:94::35) To DS4PPF0BAC23327.namprd11.prod.outlook.com (2603:10b6:f:fc02::9) Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS4PPF0BAC23327:EE_|CY8PR11MB7136:EE_ X-MS-Office365-Filtering-Correlation-Id: 9b691f20-0192-4ef0-cda4-08de7eecd476 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|376014|7416014|7053199007|22082099003|18002099003|56012099003; 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> > + device_lock_assert(&cxlmd->dev); > lockdep_assert_held(&cxl_rwsem.dpa); > lockdep_assert_held(&cxl_rwsem.region); I'm having second thoughts about this since this call site is not the 'beginning of the interfaces' as the commit msg suggests. What about taking the device lock in the debugfs func, ie - mem.c : cxl_inject_poison. If the goal is to avoid using the debugfs interface before probe completes, that does it. At this callsite, we make sure nothing changes out from under us, no endpoints attach or detach during the work. > > @@ -331,6 +332,10 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa) > { > int rc; > > + ACQUIRE(device_intr, devlock)(&cxlmd->dev); > + if ((rc = ACQUIRE_ERR(device_intr, &devlock))) > + return rc; > + > ACQUIRE(rwsem_read_intr, region_rwsem)(&cxl_rwsem.region); > if ((rc = ACQUIRE_ERR(rwsem_read_intr, ®ion_rwsem))) > return rc; > @@ -355,6 +360,7 @@ int cxl_clear_poison_locked(struct cxl_memdev *cxlmd, u64 dpa) > if (!IS_ENABLED(CONFIG_DEBUG_FS)) > return 0; > > + device_lock_assert(&cxlmd->dev); > lockdep_assert_held(&cxl_rwsem.dpa); > lockdep_assert_held(&cxl_rwsem.region); > > @@ -400,6 +406,10 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa) > { > int rc; > > + ACQUIRE(device_intr, devlock)(&cxlmd->dev); > + if ((rc = ACQUIRE_ERR(device_intr, &devlock))) > + return rc; > + > ACQUIRE(rwsem_read_intr, region_rwsem)(&cxl_rwsem.region); > if ((rc = ACQUIRE_ERR(rwsem_read_intr, ®ion_rwsem))) > return rc; > > -- > 2.43.0 >