Worked on improving reliability in the amzn/rdma-core repository by addressing a critical concurrency issue in the RXE CQ_EX polling path. Focused on low-level programming in C, the developer identified and fixed a bug where the spin lock could be unlocked twice during polling, which previously led to undefined behavior and potential system instability. The solution ensured the spin lock is released exactly once per poll cycle, aligning with man page guidance and enhancing polling stability under load. This work involved careful bug fixing and concurrency management, as well as code review and documentation to support future maintenance and system reliability.