A lightweight and portable approach to making concurrent failures reproducible

Multithreaded concurrent programs often exhibit bugs due to unintended interferences among the concurrent threads. Such bugs are often hard to reproduce because they typically happen under very specific interleaving of the executing threads. Basically, it is very hard to fix a bug (or software failure) in concurrent programs without being able to reproduce it. In this paper, we present an approach, called ConCrash, that automatically and deterministically reproduces concurrent failures by recording logical thread schedule and generating unit tests. For a given bug (fail-ure), ConCrash records the logical thread scheduling or-der and preserves object states in memory at runtime. Then, ConCrash reproduces the failure offline by simply using the saved information without the need for JVM-level or OS-level support. To reduce the runtime performance over-head, ConCrash employs a static datarace detection tech-nique to report all possible race conditions, and only in-struments such places. We implement the ConCrash ap-proach in a prototype tool for Java and experimented on a number of multithreaded Java benchmarks. We successfully reproduced a number of real concurrent bugs (e.g., dead-locks, data races, two-stage access) within an acceptable overhead.