On Thu, Jul 27, 2023 at 11:33:26PM -0700, Nicolin Chen wrote: > Update the unprotect routine in iommufd_access_destroy_object() to calling > the new iommufd_access_change_ioas() helper. This will reduce some risk of > race condition with another concurrent iommufd_access_replace/detach call. > > Note that the behavior of this function call is changed: a WARN_ON will be > triggered by a -EBUSY return code if there is another ongoing detach. This should be completely impossible, at this point the object must have a refcount of 0 so if another thread is concurrently detaching it we are already UAFing. Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx> Jason
