A decision procedure for detecting atomicity violations for communicating processes with locks

Abstract

The problem of interest is to verify data consistency of a concurrent Java program. In particular, we present a new decision procedure for verifying that a class of data races caused by inconsistent accesses on multiple fields of an object cannot occur (so-called atomic-set serializability). Atomic-set serializability generalizes the ordinary notion of a data race (i.e., inconsistent coordination of accesses on a single memory location) to a broader class of races that involve accesses on multiple memory locations. Previous work by some of the authors presented a technique to abstract a concurrent Java program into an EML program, a modeling language based on pushdown systems and a finite set of reentrant locks. Our previous work used only a semi-decision procedure, and hence provides a definite answer only some of the time. In this paper, we rectify this shortcoming by developing a decision procedure for verifying data consistency, i.e., atomic-set serializability, of an EML program. When coupled with the previous work, it provides a decision procedure for verifying data consistency of a concurrent Java program. We implemented the decision procedure, and applied it to detect both single-location and multi-location data races in models of concurrent Java programs. Compared with the prior method based on a semi-decision procedure, not only was the decision procedure 34 times faster overall, but the semi-decision procedure timed out on about 50% of the queries, whereas the decision procedure timed out on none of the queries.