[PATCH 0/5] Bluetooth: 6LoWPAN lifecycle fixes

[Cen Zhang]

6LoWPAN shares L2CAP channels between connection setup, published peers
and packet transmission, while teardown also schedules asynchronous
cleanup. These paths currently disagree on when channel ownership, peer
visibility and module lifetime end. The resulting failures range from
leaked or unusable connections and peers surviving disable to transmit
use-after-free and execution of unloaded module code.

This series establishes a consistent ownership and teardown order across
those paths. Shared L2CAP and workqueue changes provide the lifetime
guarantees needed by the following 6LoWPAN changes, which make failed setup
recoverable and stop users of a peer before releasing its resources.
Keeping the changes together avoids fixing one lifetime while shortening
another.

The timer support adds one ordered workqueue per L2CAP connection and
serializes that connection's channel timers.

Assisted-by: LLM