Debugging Concurrent Programs with Sequential Analysis

The design of concurrent programs is error-prone due to the interaction between concurrently executing threads. Traditional automated techniques for finding errors in concurrent programs, such as model checking, explore all possible thread interleavings. Since the number of thread interleavings increases exponentially with the number of threads, such analyses have high computational complexity. In this paper, we present a novel analysis technique for concurrent programs that avoids this exponential complexity. Our analysis transforms a concurrent program into a sequential program that simulates the execution of a large subset of the behaviors of the concurrent program. The sequential program is then analyzed by a tool that only needs to understand the semantics of sequential execution. Our technique never reports false errors but may miss errors. We have implemented the technique in KIS, an automated checker for multithreaded C programs, and obtained promising initial results by using KIS to detect race conditions in Windows device drivers.