Hello, I used MPI RMA in my program, but the program stop at the MPI_Win_fence, I have a master process receive data from udp socket. Other processes use MPI_Get to access data. master process: MPI_Create(...) for(...){ /* udp recv operation */ MPI_Barrier // to let other process know data received from udp is ready MPI_Win_fence(0, win); MPI_Win_fence(0, win); } other processes: for(...){ MPI_Barrier // sync for udp data ready MPI_Win_fence(0, win); MPI_Get(); MPI_Win_fence(0, win); <-- program stopped here /* other operation */ } I found that the program stopped at second MPI_Win_fence, the terminal output is: =================================================================================== = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES = EXIT CODE: 11 = CLEANING UP REMAINING PROCESSES = YOU CAN IGNORE THE BELOW CLEANUP MESSAGES =================================================================================== YOUR APPLICATION TERMINATED WITH THE EXIT STRING: Segmentation fault (signal 11) This typically refers to a problem with your application. Please see the FAQ page for debugging suggestions Do you have any suggestions? Thank you very much! -- Best Regards, Sufeng Niu ECASP lab, ECE department, Illinois Institute of Technology Tel: 312-731-7219