Trace Validation of Unmodified Concurrent Systems with OmniLink

2026-01-16

AI Summary

Verifying concurrent systems is notoriously challenging due to rare thread interleavings, and existing approaches often require invasive instrumentation or rely on unrealistic execution models. This work proposes OmniLink, a novel method that models system events as black-box operations constrained by temporal windows and leverages TLA+ semantics to infer a logical total order of actions. By doing so, OmniLink enables high-fidelity verification without modifying the target system. It transcends the limitations of traditional linearizability checking by supporting non-linearizable behaviors and remains compatible with general-purpose model checkers. Experimental evaluation demonstrates that OmniLink successfully verifies industrial and research-grade systems—including WiredTiger, BAT, and ConcurrentQueue—not only reproducing known bugs but also uncovering two previously unknown vulnerabilities, significantly outperforming state-of-the-art tools.

Technology Category

• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories
• Cognitive Modeling & Cognitive Systems: Conceptual Inference and Reasoning
• Data Mining & Knowledge Management: Scalability, Parallel & Distributed Systems

Application Category

• Security and Privacy: Data transparency and provenance
• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• Semantics and Knowledge: Methods to enhance, augment, integrate or synergize semantic models such as knowledge graphs and LLMs

Abstract

Concurrent systems are notoriously difficult to validate: subtle bugs may only manifest under rare thread interleavings, and existing tools often require intrusive instrumentation or unrealistic execution models. We present OmniLink, a new methodology for validating concurrent implementations against high-level specifications in TLA+. Unlike prior TLA+ based approaches which use a technique called trace validation, OmniLink treats system events as black boxes with a timebox in which they occurred and a meaning in TLA+, solving for a logical total order of actions. Unlike prior approaches based on linearizability checking, which already solves for total orders of actions with timeboxes, OmniLink uses a flexible specification language, and offers a different linearizability checking method based on off-the-shelf model checking. OmniLink offers different features compared existing linearizability checking tools, and we show that it outperforms the state of the art on large scale validation tasks. Our evaluation validates WiredTiger, a state-of-the-art industrial database storage layer, as well as Balanced Augmented Tree (BAT), a state-of-the art lock-free data structure from the research community, and ConcurrentQueue, a popular lock-free queue featuring aggressive performance optimizations. We use OmniLink to improve WiredTiger's existing TLA+ model, as well as develop new TLA+ models that closely match the behavior of the modeled systems, including non-linearizable behaviors. OmniLink is able to find known bugs injected into the systems under test, as well as help discover two previously unknown bugs (1 in BAT, 1 in ConcurrentQueue), which we have confirmed with the authors of those systems.

Problem

• concurrent systems
• trace validation
• TLA+
• linearizability checking
• formal verification

Innovation

• OmniLink
• trace validation
• concurrent systems
• TLA+
• linearizability checking