diff mbox series

[v10,17/22] vfio: Move vfio_device_group_unregister() to be the first operation in unregister

Message ID 20230426150321.454465-18-yi.l.liu@intel.com (mailing list archive)
State New, archived
Headers show
Series Add vfio_device cdev for iommufd support | expand

Commit Message

Yi Liu April 26, 2023, 3:03 p.m. UTC 
This can avoid endless vfio_device refcount increasement by userspace,
which would keep blocking the vfio_unregister_group_dev().

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
 drivers/vfio/vfio_main.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index c0459872d79a..c3263cb2ea75 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -322,6 +322,12 @@  void vfio_unregister_group_dev(struct vfio_device *device)
 	bool interrupted = false;
 	long rc;
 
+	/*
+	 * Prevent new device opened by userspace via the
+	 * VFIO_GROUP_GET_DEVICE_FD in the group path.
+	 */
+	vfio_device_group_unregister(device);
+
 	vfio_device_put_registration(device);
 	rc = try_wait_for_completion(&device->comp);
 	while (rc <= 0) {
@@ -345,8 +351,6 @@  void vfio_unregister_group_dev(struct vfio_device *device)
 		}
 	}
 
-	vfio_device_group_unregister(device);
-
 	/* Balances device_add in register path */
 	device_del(&device->device);