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vfio/mdev: Add missing reference counting to mdev_type

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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>
This commit is contained in:
Jason Gunthorpe 2021-04-06 16:40:30 -03:00 committed by Alex Williamson
parent a9f8111d0b
commit 9a302449a5
1 changed files with 4 additions and 0 deletions
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4
drivers/vfio/mdev/mdev_sysfs.c
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@ -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),