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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?GxRislB6q9CP4HH4NI8KwlKHyGnpXdypBaadHCJe3WxUiUjzK1RkEZRRh5mk?= =?us-ascii?Q?Mo/24z43yj9ZXC0UYUHo1AeF+8dffg/0wBsHRqw1Gl9XGET+PHLyKAMEVDkh?= =?us-ascii?Q?JnnbyZIx1acojL1HTLg0WmUrX+Hp5wbqvB1m9GsZlrU9dKQ7QQONxGDUZAK4?= =?us-ascii?Q?tspL6byzXs6TQFg6Zcej+jwsEZa5Ce9nNJCIrK2unEjohs4bEWw65bmAS0JE?= =?us-ascii?Q?isvs0DWM1I/ZJusPIMpidRYtjoenLcn7pETE50frq1E0oaBrwNZc0tm0JrH4?= =?us-ascii?Q?xIIVSnMOcNkjM6MvI6hLMxxqRz+SBOJd9/i7mgS9mcI+P8X741VKBQL70E6g?= =?us-ascii?Q?Y+jGDqKkSIkisR964cpkoklkmvs3UYH+fM+pOHvUwqMl73aciRouqut4Etwq?= =?us-ascii?Q?NEDDrlQL4JGE0WkPTBUccy9Perz413vIvSObgCc9g3VB/Jc3JDOLBn4hk1R4?= =?us-ascii?Q?d0dWrpHEWhJbBsMlESMhaoceNoRg90q9qpljG4/orLEGX6x/RTTFmwA/DBX5?= =?us-ascii?Q?HlqU4BEfHxXb9EDSZvyz2d/L5d3fkdha/k4b9PISveBsJ+aOUhdJgVQE0dXl?= =?us-ascii?Q?k9Pn+ytR+LIQDIcfUKxIKG3gFlLeuceRC6uy7fh2wVhERS3Y8CsMFsGvQHcO?= =?us-ascii?Q?U64zcBVaqeRgJ81SV/VQX+7FHzvafozYtZX2XSF++Q3uEzL+/MwJXslkEyVd?= =?us-ascii?Q?txrrhBL+Xm29eFcAUKTb/bEeSkEOlLX7fAXdoLaRgAmgiT4oYQEGcy/PqiU3?= =?us-ascii?Q?gx/qo7A5+QDTalVkZ6JFSIhyzK/5ZKsusL4/0bDyEG0LvqS0Nbx86oHmB27y?= =?us-ascii?Q?hAxB6z8vhMLE52gXF3XuatTMvSyJgLnkwEqkSi4tNZRnUJhKUJK8aAYuQb4J?= =?us-ascii?Q?ljIPwswc9rLdYmPain3BimbTmxTit5ZC73UHBprUHkQv5G/fnJdGr2xJW5gk?= =?us-ascii?Q?1RIKtwrPq3EEgclr9UhunkAimzcktuOz5R73MTQETMJRyc+ajeYOd07HovEy?= =?us-ascii?Q?To+TwTNLEfWHNHXCzaPlwVUF9f0Jr/hbBeib105OE5w6hTG98G2Gs7Vul7WC?= =?us-ascii?Q?twFSbBakGdh3bLVA8VopBmC7E3h/f14QdVLP3BA6R/wcKbp4RUoHbp5wq/yk?= =?us-ascii?Q?EFOo1nrtGEAZiIYtn+ZHiSaa/G/Lu/pQ/O2NeDHPfWqifGADJYA83bEdecmU?= =?us-ascii?Q?R/xmBNIMwE7Sr5DstC/xuag18CoaOyhChF5nbAJyf42QdGbd2OACmGRJhIz1?= =?us-ascii?Q?UygirAZPsjho+PfL9Aitsj3RJTfITcldatS1u0kIzZtGBr2cg09KG6jS2zGd?= =?us-ascii?Q?ZFniZ8tSna4Y9tM6XtG+UcxgEP2eRXKOrFVLEjV1fH2+I05l8l8S1oPiTkmu?= =?us-ascii?Q?kF+6dY6Z2L1W+azfzAStCEA9C6iivqolx6kzGfh5c3mtW3m5SxWqCE88mS7e?= =?us-ascii?Q?37uo/4pM52n+ukls7vnOJk/y4Uk1tnvRE8g5nxXHxBOldbT5lVCfjZm5gW3C?= =?us-ascii?Q?gcQh7Rcc/o4x7+1IRx2Db7rEu2I0HQcT724kn9LVZhn4VKNmzGs+U6FqwfnI?= =?us-ascii?Q?pef/g17rqSDVH99O3n74+pK258krO8IRAa0AgazB?= X-MS-Exchange-CrossTenant-Network-Message-Id: 3476e64f-11e8-43fa-61bb-08dbc14717e9 X-MS-Exchange-CrossTenant-AuthSource: SA1PR11MB6733.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 Sep 2023 23:52:09.2283 (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: dM6E9aupD9gZFDYA/a/0zl5u3NdcvErvZ0a82ms2afWC5h16YP6QQOoqQNSb29pbi3SRM3SHSsa5ty7RRGYLCg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR11MB7335 X-OriginatorOrg: intel.com Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org Dan Williams wrote: > Ira reports that removing cxl_mock_mem causes a crash with the following > trace: > > BUG: kernel NULL pointer dereference, address: 0000000000000044 > [..] > RIP: 0010:cxl_region_decode_reset+0x7f/0x180 [cxl_core] > [..] > Call Trace: > > cxl_region_detach+0xe8/0x210 [cxl_core] > cxl_decoder_kill_region+0x27/0x40 [cxl_core] > cxld_unregister+0x29/0x40 [cxl_core] > devres_release_all+0xb8/0x110 > device_unbind_cleanup+0xe/0x70 > device_release_driver_internal+0x1d2/0x210 > bus_remove_device+0xd7/0x150 > device_del+0x155/0x3e0 > device_unregister+0x13/0x60 > devm_release_action+0x4d/0x90 > ? __pfx_unregister_port+0x10/0x10 [cxl_core] > delete_endpoint+0x121/0x130 [cxl_core] > devres_release_all+0xb8/0x110 > device_unbind_cleanup+0xe/0x70 > device_release_driver_internal+0x1d2/0x210 > bus_remove_device+0xd7/0x150 > device_del+0x155/0x3e0 > ? lock_release+0x142/0x290 > cdev_device_del+0x15/0x50 > cxl_memdev_unregister+0x54/0x70 [cxl_core] > > This crash is due to the clearing out the cxl_memdev's driver context > (@cxlds) before the subsystem is done with it. This is ultimately due to > the region(s), that this memdev is a member, being torn down and expecting > to be able to de-reference @cxlds, like here: > > static int cxl_region_decode_reset(struct cxl_region *cxlr, int count) > ... > if (cxlds->rcd) > goto endpoint_reset; > ... > > Fix it by keeping the driver context valid until memdev-device > unregistration, and subsequently the entire stack of related > dependencies, unwinds. > > Fixes: 9cc238c7a526 ("cxl/pci: Introduce cdevm_file_operations") > Reported-by: Ira Weiny Reviewed-by: Ira Weiny Tested-by: Ira Weiny