Debugging Concurrency and Unsafe Patterns — Forge College

Can code that compiles still produce undefined behavior on Solana? Concurrency and unsafe Rust can silently break memory safety and determinism — this lesson shows you how to reproduce, diagnose, and fix those failures. What you'll learn In this guided debugging lab you will learn to produce a minimal reproducible test that exposes concurrency-related undefined behavior caused by combining raw pointers, unsafe blocks, and threads. You will trace root causes such as data races, aliasing that leads to use-after-free, and incorrect UnsafeCell / static mut usage. The lesson covers practical diagnostics with tools like Miri and loom, how to add dev-dependencies in Cargo.toml, and how to structure tests (for example tests/bug_repro.rs) to exercise problematic interactions reliably. You will apply concrete fixes—synchronization primitives, safer APIs, or removing unsafe aliasing—and validate them with deterministic tests or analyzer output. Who this is for Intermediate Rust developers working with Solana programs or off-chain Rust workers. You should already be comfortable with ownership, lifetimes, borrowing, and basic Solana program constraints. Key topics covered - Reproducing concurrency and unsafe bugs with minimal tests - Diagnosing data races and unsynchronized shared mutation - Aliasing via raw pointers and use-after-free scenarios - UnsafeCell and static mut pitfalls that break memory invariants - Using Miri and loom for UB and concurrency testing - Writing a short debug report documenting reproduction, root cause, and patch Ready to build safer Solana programs and robust debug reports? Start here: https://www.forge.college/