Commit 9a302449 authored Apr 06, 2021 by Jason Gunthorpe Committed by Alex Williamson Apr 07, 2021

vfio/mdev: Add missing reference counting to mdev_type



struct mdev_type holds a pointer to the kref'd object struct mdev_parent,
but doesn't hold the kref. The lifetime of the parent becomes implicit
because parent_remove_sysfs_files() is supposed to remove all the access
before the parent can be freed, but this is very hard to reason about.

Make it obviously correct by adding the missing get.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <7-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

parent a9f8111d

drivers/vfio/mdev/mdev_sysfs.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -81,6 +81,8 @@ static void mdev_type_release(struct kobject *kobj)
		struct mdev_type *type = to_mdev_type(kobj);

		pr_debug("Releasing group %s\n", kobj->name);
		/* Pairs with the get in add_mdev_supported_type() */
		mdev_put_parent(type->parent);
		kfree(type);
		}

		@@ -106,6 +108,8 @@ static struct mdev_type add_mdev_supported_type(struct mdev_parent parent,

		type->kobj.kset = parent->mdev_types_kset;
		type->parent = parent;
		/* Pairs with the put in mdev_type_release() */
		mdev_get_parent(parent);

		ret = kobject_init_and_add(&type->kobj, &mdev_type_ktype, NULL,
		"%s-%s", dev_driver_string(parent->dev),