Hi, note that opensm can be run as a daemon -- are you sure there are no other instances running on the system? If no, then you may be missing some of the underlying userspace libraries needed for the SM to function correctly?
Which ConnectX-3 card are you using? Can you run:
# lspci -v | grep Mellanox
Also, are the port in InfiniBand mode? Can you run:
# connectx_port_config
Also, do you have the correct (and latest) firmware version installed? Can you run:
# ibstat