We present an approach for the verification of Erlang programs using abstract interpretation and model checking. In previous work we defined a framework for abstract interpretations for Erlang. In this framework it is guaranteed, that the abstract operational semantics preserves all paths of the standard operational semantics. We consider properties that have to hold on all paths of a system, like properties in LTL. If these properties can be proven for the abstract operational semantics, then they also hold for the Erlang program. The proof can be automated with model checking if the abstract operational semantics is a finite transition system. But finiteness cannot be guaranteed interpretations we get infinite state systems and model checking is undecidable. In this paper we define an abstraction of the control-flow. It replaces the recursive calls in non-tail positions by jumps to the last call of the same function. The corresponding returns are replaced by jumps to the possible return points. We have implemented this approach as a prototype and are able to prove properties like mutual exclusion or the absence of deadlocks and lifelocks for some Erlang programs.

Several years of experience with the functional language Erlang have learned Ericsson that it is highly beneficial to use this language for programming control software for large systems. Systems that could not be built before, have been constructed in less time and with fewer lines of code than one would need with conventional languages. The success of Ericsson in the business area of telephone switches is partly because of their solid fault tolerant architecture, both in hardware and in software. A lot of time and money have been invested in the development of this fault tolerant architecture, all to catch these errors that are overlooked in numerous tests. By using Erlang and its extensive libraries, the number of these uncaught errors decreases; the fault recovery mechanism of the system is used less. One saves on maintenance costs and the overall performance of a system increases. The additional use of formal verifiation aims on reducing even more the number of uncaught errors.