Worked on the microsoft/mscclpp repository to address a critical stability issue in CUDA-based NVLS tests under CUDA 12.9. Focused on resolving an illegal memory access bug in the nvls_test by carefully reordering memory operations, specifically moving the cudaMemset call after memory mapping and access setup. This adjustment ensured proper memory initialization and prevented access violations, thereby improving runtime stability and compatibility with CUDA 12.9. Utilized C++ and CUDA for debugging, memory management, and testing, demonstrating a methodical approach to incremental test fixes. The work enhanced the reliability of the test suite without introducing new features during the period.