Release serial by device path before serial connection
For serial connection, lava uses ser2net, but engineer may use cat, screen or minicom for debugging. When there is session left in the background, LAVA will fail to establish connection. Always release serial by device path first sound like a good improvement.
@artem.kondratiuk proposed to use sudo fuser -k <serial_path>. It is to be tested in LAVA. For this improvement, all related scripts and lava device configs should be updated.