Modular Verification of Concurrent Programs via Sequential Model Checking

TL;DR

This paper presents a modular approach to verify concurrent programs by reducing their verification to sequential program checks, exploiting hierarchical thread structures to improve efficiency and enabling the use of existing sequential model checkers.

Contribution

It introduces a hierarchical, modular verification method for concurrent programs that reduces the problem to sequential verification tasks, enhancing automation and efficiency.

Findings

Effective on hierarchically structured programs

Utilizes existing sequential model checkers

Demonstrates improved performance over established tools

Abstract

This work utilizes the plethora of work on verification of sequential programs for the purpose of verifying concurrent programs. We reduce the verification of a concurrent program to a series of verification tasks of sequential programs. Our approach is modular in the sense that each sequential verification task roughly corresponds to the verification of a single thread, with some additional information about the environment in which it operates. Information regarding the environment is gathered during the run of the algorithm, by need. While our approach is general, it specializes on concurrent programs where the threads are structured hierarchically. The idea is to exploit the hierarchy in order to minimize the amount of information that needs to be transferred between threads. To that end, we verify one of the threads, considered "main", as a sequential program. Its verification process initiates queries to its "environment" (which may contain multiple threads). Those queries are answered by sequential verification, if the environment consists of a single thread, or, otherwise, by applying the same hierarchical algorithm on the environment. Our technique is fully automatic, and allows us to use any off-the-shelf sequential model checker. We implemented our technique in a tool called CoMuS and evaluated it against established tools for concurrent verification. Our experiments show that it works particularly well on hierarchically structured programs.