During January 2025, Xiayu Yu contributed to the gem5/gem5 repository by addressing a robustness issue in the memory system simulation. Focusing on the VIPERSequencer component, Xiayu debugged and resolved an assertion failure that occurred when multiple compute units issued hasNoAddr requests, which could result in a null ruby_request during processReadCallback. By reissuing these requests as needed, the fix stabilized the VIPERSequencer path for arch-vega integration and reduced simulation failures. Working primarily in C++ and leveraging expertise in debugging and system simulation, Xiayu’s targeted change improved the reliability and crash resistance of long-running memory subsystem models.