In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: hci_event: fix potential UAF in hci_le_remote_conn_param_req_evt

hci_conn lookup and field access must be covered by hdev lock in
hci_le_remote_conn_param_req_evt, otherwise it's possible it is freed
concurrently.

Extend the hci_dev_lock critical section to cover all conn usage.