Can't create RFCOMM TTY: Address already in use

Question

The following error occurs when I issue sudo rfcomm listen rfcomm0

Can't create RFCOMM TTY: Address already in use

I received some serial Bluetooth data in a Python program beforehand. So, it seems something gets stuck.

Then I type sudo rfcomm release rfcomm0 which yields:

Can't release device: Operation already in progress

How can I make a hard release? For now the only way to get it working again is to reboot.

Answer 1

Ok since rebooting is annoying, I have tried two approaches.

• Create another device and bind the bluetooth to it. Then use the new one in your program.

Open /etc/bluetooth/rfcomm.conf and add another device.

rfcomm0 { # Automatically bind the device at startup bind no; # Bluetooth address of the device device 00:06:66:68:20:61; # RFCOMM channel for the connection channel 1; # Description of the connection comment "This is Device 1's serial port."; }

rfcomm2 { # Automatically bind the device at startup bind no; # Bluetooth address of the device device 20:15:12:08:62:95; # RFCOMM channel for the connection channel 1; # Description of the connection comment "This is Device 1's serial port."; }

rfcomm3 { # Automatically bind the device at startup bind no; # Bluetooth address of the device device 20:15:12:08:62:95; # RFCOMM channel for the connection channel 1; # Description of the connection comment "This is Device 1's serial port."; }

Restart the bluetooth service then :

userk@dopamine:~$ sudo rfcomm bind 2 DEV_ADDR CHANNEL

• The answer:

Rfcomm can't release the device because of some other process in Ubuntu. Check which one with

userk@dopamine:~$ sudo lsof | grep /dev/rfcomm2

MATLAB    5554 6868            userk  514u      CHR              216,2       0t0        603 /dev/rfcomm2

Kill it!!

userk@dopamine:~$ ps -ax | grep MATLAB
 7684 pts/5    Sl     0:39 /usr/local/MATLAB/R2015b/bin/glnxa64/MATLAB
 7873 pts/5    S+     0:00 grep --color=auto MATLAB

userk@dopamine:~$ kill -9 7684

Voilà no ore forced reboot! Hope it helps

Answer 2

Quite late here but I had this same issue on Ubuntu 16.04.

What I did was the following:

sudo service bluetooth restart

Which gave me the error:

Warning: bluetooth.service changed on disk. Run 'systemctl daemon-reload' to reload units.

After running the suggested command in the warning I was able to succesfully restart the bluetooth service and commence listening on the port.

I suspect that in my case I changed a config (running bluetoothd with the --compat argument) and therefor the init system had to reload.