Atomically updating shared data in a transactional memory system comprising transactional memory storage and a transactional memory enabled processor. The computer creates a pointer stored in a stable memory location that is used to locate a shared data stored in a second memory location. The computer accesses the shared data and loads the pointer used to locate the accessed shared data into transactional memory storage. The computer updates the accessed shared data using copy-on-write, whereby the updated shared data is stored in a third memory location, and performs the atomic update of the shared data by updating the pointer such that it locates the updated shared data stored in the third memory location.