In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix deadlock in l2cap_conn_del() l2cap_conn_del() calls cancel_delayed_work_sync() for both info_timer and id_addr_timer while holding conn->lock. However, the work functions l2cap_info_timeout() and l2cap_conn_update_id_addr() both acquire conn->lock, creating a potential AB-BA deadlock if the work is already executing when l2cap_conn_del() takes the lock. Move the work cancellations before acquiring conn->lock and use disable_delayed_work_sync() to additionally prevent the works from being rearmed after cancellation, consistent with the pattern used in hci_conn_del().
https://git.kernel.org/stable/c/d008460de352e534f6721de829b093368564ec66
https://git.kernel.org/stable/c/3f26ecbd9cde621dd94be7ef252c7210b965a5c7
https://git.kernel.org/stable/c/00fdebbbc557a2fc21321ff2eaa22fd70c078608