在循环内调用MPI_Reduce时出现致命错误

int MPI_Reduce(const void *sendbuf, void *recvbuf, int count, MPI_Datatype datatype, MPI_Op op, int root, MPI_Comm comm)

#include <mpi.h>

int main(int argc, char** argv) {
    int rank, size;
    int sum = 0;
    int i;

    MPI_Init(&argc, &argv);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &size);

    for (i = 0; i < size; i++) {
        sum += rank;
    }

    int total_sum;
    MPI_Reduce(&sum, &total_sum, 1, MPI_INT, MPI_SUM, 0, MPI_COMM_WORLD);

    if (rank == 0) {
        printf("Total sum: %d\n", total_sum);
    }

    MPI_Finalize();

    return 0;
}