There was a reference counting problem in the TPC logic of net_clone(). ...

There was a reference counting problem in the TPC logic of net_clone().  net_clone() which is the common logic underlying dup() and dup2() for sockets.  When net_clone() calls net_start_monitor() and net_start_monitor() returns a failure (because the underlying TCP connection) then net_clone() must back out the reference count on the structure.  Problem noted by Pascal Speck and this implementation of the solution is based on his suggestion.