Location: 510 Soda
Date: Thursday, May 1, 2025
Time: 11:00 AM PST
Title: Back to Basics—Controlled Concurrency Testing for JVM Programs
Abstract:
In multi-threaded programs, concurrency bugs are notoriously hard to discover and reproduce. Despite decades of research on sophisticated algorithms for concurrency testing, e.g., via probabilistic and partial-order-based sampling of thread interleavings, the state-of-the-practice for most Java developers has been to just run stress tests in a loop. It turns out that none of the fancy algorithms could be readily applied because no prior tool could efficiently, easily, and correctly control thread-level non-determinism in real-world applications. This talk will present Fray, our new framework for push-button concurrency testing of JVM programs that is explicitly designed with the goal of general-purpose applicability. Fray employs a concurrency control mechanism we call “shadow locking”, which guarantees soundness and completeness of expressiveness under a reasonable set of assumptions, and is more efficient than classical OS-level or JVM-simulation-based approaches to managing concurrency. Fray works out-of-the-box on production-grade software such as Apache Kafka, Apache Lucene, and Google Guava—we have shown how hundreds of existing unit tests in these mature projects can fail under certain interleavings, and have helped developers confirm and debug over a dozen new bugs.
Bio:
Rohan Padhye is an Assistant Professor in the School of Computer Science at Carnegie Mellon University, where he leads the Program Analysis, Software Testing, and Applications (PASTA) lab in the Software and Societal Systems Department (S3D). Rohan’s key contributions are in the area of fuzz testing and concurrency analysis. His work has received multiple distinguished/best paper and tool/artifact awards, and has helped uncover hundreds of software bugs in widely used open-source and commercial software. Rohan holds a Ph.D. in Computer Science from UC Berkeley, where he received the C.V. Ramamoorthy Distinguished Research Award. He has also worked with Amazon Web Services, Microsoft, Samsung, and IBM Research in various capacities.