Transient devices pose a special challenge for an operating-system kernel. They can disappear at any time, leaving behind kernel data structures that no longer refer to an existing device, but which may still be in use by unknown kernel code. Managing the resulting lifecycle issues has frustrated kernel developers for years. In September 2025, the revocable resource-management patch series from Tzung-Bi Shih appeared to offer a partial solution to this problem. Since then, though, other problems have arisen, and the planned merging of this series into the 7.0 release has been called off.