  We present an algorithm for the repair of parameterized systems. The repair
problem is, for a given process implementation, to find a refinement such that
a given safety property is satisfied by the resulting parameterized system, and
deadlocks are avoided. Our algorithm uses a parameterized model checker to
determine the correctness of candidate solutions and employs a constraint
system to rule out candidates. We apply this algorithm on systems that can be
represented as well-structured transition systems (WSTS), including disjunctive
systems, pairwise rendezvous systems, and broadcast protocols. Moreover, we
show that parameterized deadlock detection can be decided in EXPTIME for
disjunctive systems, and that deadlock detection is in general undecidable for
broadcast protocols.
