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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?zook820jnTYxzlqw4kLCACzhJwJavyn25Hvbou6RdsG+AS5EoeEYHPnyEgVs?= =?us-ascii?Q?VN8ljZ0QRuKtEIp0mP1X65K2Jws/sLlGzP8s6TXVuVNC1JoNCWiIhpYcrtcX?= =?us-ascii?Q?YJOafLQWCSwvcFJBphhN9ZisNynPb6x5q1vNhZK+8b3vL4J3nTcoDscMW/Pc?= =?us-ascii?Q?3ggYRsunqMMgSujHzCzH0EJ9ey8kQCwdOPinGZPk7/EtfYkoDgYmznuiTCc9?= =?us-ascii?Q?wbYqE5RUBh0anzlsLiGDCivCtHFZC7EZeaRhLzQhe/+d0kiNF6NtipBywhpe?= =?us-ascii?Q?mxKUHo1n1TDD8kd2eGEeef0uN78ZWCWUnRe1tTYBc5m7lQujiAxDPVcZiCaC?= =?us-ascii?Q?qdXxAcxintfkPPz2c3BizahQjqLAGTGli7jPJu7typl4wlxo4RcmD4YZ4FxU?= =?us-ascii?Q?Wo591DlQ/vzqSSwiJ1fmoNc+u+3OO4+TakiTt7y26VV/kn2IBzI42+5aVw0/?= =?us-ascii?Q?8Gs+QyMqVDLeonk4/4sJlEaqdWZYTH4XWonVeJ87PttMAP62pgSOgqlO1LZv?= =?us-ascii?Q?KIEnGsgW5pccTviKmbc2l47tbGZwWJoEKdPxWgOl068aTfqw+n4n2G1OYtXS?= =?us-ascii?Q?hAUNiCcx/L5inO+xdCtWrck8Dhteh/o3AXgG04iQ9taJ+L9It5xDZ48jGyQJ?= =?us-ascii?Q?XDsYNh46zfwHGcStJ+X+BS89zgtjh8w89SSSJjk8ztxb8KxiOUHML/aDtniH?= =?us-ascii?Q?gxt87/hWULE2Aw1k51dVoulh5/rXzfd42nIC5QHiAaYCOYZ59DWz3DCU92cm?= =?us-ascii?Q?p9ZvwFKIvpvEsc0GU2H/wiBa8usNxCCAQORHLRMvJyR2q9IxlZv72MLxJoz7?= =?us-ascii?Q?ycbyor5D8B6VfxZvdbhnsPARpKspGfn00NrdHA45xR5lnDgLlRqDzyKXrdil?= =?us-ascii?Q?+YCUrtVcEHEeJmGIsaXzLX11B1cveOfOTvBnfe5PM7cPIspFN6SSB3ZizibF?= =?us-ascii?Q?XrcrbDRwEMSfbmgH6m83RIGPCwW/a1I0fc1VLda7MLCMl6H8A2c7j4WrKYtB?= =?us-ascii?Q?Boe+mCaO7KYTBNiihJuh1BGg1ZI9dG8K4OfxaNUc3ILscidYGrdqSFar5Kkf?= =?us-ascii?Q?8+XZ8BRMbU15zvvMPab5n4TIe0JEKigk6cOq3WUM/z8bnPr6PK0oIzJbN6jL?= =?us-ascii?Q?HZLW254wtCIw1B353ehz5RIU6Z8BvoPlpJYE4RJCprMWkbpIFC5+T1PBCl0V?= =?us-ascii?Q?/24Lm1Aa+CRa/5EjG3cTyHajbz3ZoT7f5cScrRMXOjL67D24izEdcv2T8cSW?= =?us-ascii?Q?l0RZAOM0oCAPBn+EoXmjNWSPdV0gFQB9BVbIl6sRxOlMwOOc540vozB2iixc?= =?us-ascii?Q?w50XMWnirHKqcogqhYusKEnRu9aXrOPXx2mgLhADAQuzGcYdBIPPwfMiikgt?= =?us-ascii?Q?p4wbWG3esBOMtTEZ3zV+nGTzn6JSpFStOG8ixH5IQ5iCvhCkDzEDOOFQQq+h?= =?us-ascii?Q?BqpSoQgSnj3YudHm5kc4xDU+L+5ZK1Ta6eIPhSyX19IQmx012t3IcVILh82O?= =?us-ascii?Q?ZuZ9H8lICFyEqQxT5SdfJ1kKlhDOLPnxKY+ySTZhlcCvtcsLiOw4U2iwDyXZ?= =?us-ascii?Q?X0p5jLLibfTg5UpFFmN7Aq+OYPrnF0dqxIrBxP0D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: aba9a2ca-fb24-4fca-f169-08ddb898a94b X-MS-Exchange-CrossTenant-AuthSource: CH3PR12MB8659.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Jul 2025 12:13:17.4938 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: VWpuX7B1StJsTn4pnZqYYJJqUugNyZwdcdvYmA00/C8ELZbNNRmVwD+AbYj3EOAr X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA0PPF002462CFE On Tue, Jul 01, 2025 at 05:19:05PM +0800, Xu Yilun wrote: > On Mon, Jun 30, 2025 at 11:50:51AM -0300, Jason Gunthorpe wrote: > > On Mon, Jun 30, 2025 at 06:18:50PM +0800, Xu Yilun wrote: > > > > > I need to reconsider this, seems we need a dedicated vdev lock to > > > synchronize concurrent vdev abort/destroy. > > > > It is not possible to be concurrent > > > > destroy is only called once after it is no longer possible to call > > abort. > > I'm almost about to drop the "abort twice" idea. [1] > > [1]: https://lore.kernel.org/linux-iommu/20250625123832.GF167785@nvidia.com/ > > See from the flow below, > > T1. iommufd_device_unbind(idev) > iommufd_device_destroy(obj) > mutex_lock(&idev->igroup->lock) > iommufd_vdevice_abort(idev->vdev.obj) > mutex_unlock(&idev->igroup->lock) > kfree(obj) > > T2. iommufd_destroy(vdev_id) > iommufd_vdevice_destroy(obj) > mutex_lock(&vdev->idev->igroup->lock) > iommufd_vdevice_abort(obj); > mutex_unlock(&vdev->idev->igroup->lock) > kfree(obj) > > iommufd_vdevice_destroy() will access idev->igroup->lock, but it is > possible the idev is already freed at that time: > > iommufd_destroy(vdev_id) > iommufd_vdevice_destroy(obj) > iommufd_device_unbind(idev) > iommufd_device_destroy(obj) > mutex_lock(&idev->igroup->lock) > mutex_lock(&vdev->idev->igroup->lock) (wait) > iommufd_vdevice_abort(idev->vdev.obj) > mutex_unlock(&idev->igroup->lock) > kfree(obj) > mutex_lock(&vdev->idev->igroup->lock) (PANIC) > iommufd_vdevice_abort(obj) > ... Yes, you can't touch idev inside the destroy function at all, under any version. idev is only valid if you have a refcount on vdev. But why are you touching this lock? Arrange things so abort doesn't touch the idev?? Jason