faux-mgs allows us to attach to a gimlet's serial console via the SP. While faux-mgs is running, it ensures it's regularly sending serial console-related packets (either writes if there's data, or keeepalives if there isn't). On a clean exit, faux-mgs will detach itself from the console. But on a non-clean exit, the SP is responsible for eventually timing out the connection and allowing new attach requests. However, it looks like only check for staleness at

This is inside the code path for "the SP has serial console data to send to faux-mgs". If the console is idle (e.g., someone left it sitting at a shell prompt), the SP will never send data, so will never realize the faux-mgs client has gone away. This isn't a major problem, because faux-mgs can forcibly detach any previous session, but it is annoying because it makes it look like there might be someone else on the console when there isn't. A pretty easy fix would be to also check for staleness in serial_console_attach().