Worked on the renesas/zephyr repository to address a critical thread-safety issue in the core synchronization primitives. Focused on the read-write lock implementation, the developer identified and resolved a race condition that previously allowed a write lock to be acquired while read locks were still active. This targeted patch, delivered as a single commit, improved reliability and stability for concurrent workloads by reducing the risk of data corruption and deadlocks. The solution was implemented in C, leveraging skills in concurrent and system programming, and aligned with repository conventions to ensure maintainability and support for future contributions in multi-threaded environments.