Sharding the State Machine: Automated Modular Reasoning for Complex Concurrent Systems


Travis Hance and Yi Zhou, Carnegie Mellon University; Andrea Lattuada, VMware Research; Reto Achermann, University of British Columbia; Alex Conway, VMware Research; Ryan Stutsman, VMware Research and University of Utah; Gerd Zellweger, VMware Research; Chris Hawblitzel, Microsoft Research; Jon Howell, VMware Research; Bryan Parno, Carnegie Mellon University


We present IronSync, an automated verification framework for concurrent code with shared memory. IronSync scales to complex systems by splitting system-wide proofs into isolated concerns such that each can be substantially automated. As a starting point, IronSync's ownership type system allows a developer to straightforwardly prove both data safety and the logical correctness of thread-local operations. IronSync then introduces the concept of a Localized Transition System, which connects the correctness of local actions to the correctness of the entire system. We demonstrate IronSync by verifying two state-of-the-art concurrent systems comprising thousands of lines: a library for black-box replication on NUMA architectures, and a highly concurrent page cache.

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@inproceedings {288564,
author = {Travis Hance and Yi Zhou and Andrea Lattuada and Reto Achermann and Alex Conway and Ryan Stutsman and Gerd Zellweger and Chris Hawblitzel and Jon Howell and Bryan Parno},
title = {Sharding the State Machine: Automated Modular Reasoning for Complex Concurrent Systems},
booktitle = {17th USENIX Symposium on Operating Systems Design and Implementation (OSDI 23)},
year = {2023},
isbn = {978-1-939133-34-2},
address = {Boston, MA},
pages = {911--929},
url = {},
publisher = {USENIX Association},
month = jul

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