Linux console client hangs

I'm running a virtual here server on a Raspberry Pi and connecting a number of FTDI serial converters on the pi. That works wonderfully, and I can connect to the Pi using the Virtual Here client to access the serial ports just fine.

On a Ubuntu 14.04 server system I'm running the Virtual Here console client in daemon mode to access the ports. This also works great, at least normally. Sometimes the client stops providing the USB devices to the Ubuntu system. The symptoms are that the ports simply vanish from the Ubuntu machine. The client is still running as a daemon, and will accept "LIST", showing the IP of the Pi. When told to "LIST LICENSES" it will return nothing. The client will not respond to "EXIT" requests, and takes a long time to die when issued a kill -9.

Restarting the Virtual Here server on the Pi makes no difference. Unplugging and replugging USB devices makes no difference. The only way to get out of this situation is to kill -9 the client on the Ubuntu machine and start a new one.

Any ideas what might be wrong, and how to avoid this happening?

Jesper

#2

Its likely a bug in linux, ill try to research the problem anyway:

when it locks can you do this:

open a new terminal in ubuntu then type

sudo sh -c "echo l > /proc/sysrq-trigger"

then email mail [at] virtualhere.com (mail[at]virtualhere[dot]com) with the contents of /var/log/syslog as that will show the outstanding driver stack in the kernel which may point to the problem.