intra-group.cl: error: possible write-write race on ((char*)p)[4092]:

intra-group.cl:3:23: write by thread (0, 0, 0) group (0, 0, 0)
  p[get_local_id(0) + get_local_size(0) - 1] = get_local_id(0);

intra-group.cl:2:5:  write by thread (1023, 0, 0) group (0, 0, 0)
  p[get_local_id(0)] = get_local_id(0);