On Interference Abstractions

Interference is the bane of both concurrent programming and analysis. To avoid considering all possible interferences between concurrent threads, most automated static analysis employ techniques to approximate interference, e.g., by restricting the thread scheduler choices or by approximating the transition relations or reachable states of the program. However, none of these methods are able to reason about interference directly. In this paper, we introduce the notion of interference abstractions (IAs), based on the models of shared memory consistency, to reason about interference efficiently. IAs differ from the known abstractions for concurrent programs and cannot be directly modeled by these abstractions. Concurrency bugs typically involve a small number of unexpected interferences and therefore can be captured by small IAs. We show how IAs, in the form of both over- and under-approximations of interference, can be obtained syntactically from the axioms of sequential consistency. Further, we present an automatic method to synthesize IAs suitable for checking safety properties. Our experimental results show that amall IAs are often sufficient to check properties in realistic applications, and drastically improve the scalability of concurrent program analysis in these applications.