The stable problem of the black-hole connected region in the Schwarzschild black hole

The stability of the Schwarzschild black hole is studied. Using the Painlev\'{e} coordinate, our region can be defined as the black-hole-connected region(r>2m, see text) of the Schwarzschild black hole or the white-hole-connected region(r>2m, see text) of the Schwarzschild black hole. We study the stable problems of the black-hole-connected region. The conclusions are: (1) in the black-hole-connected region, the initially regular perturbation fields must have real frequency or complex frequency whose imaginary must not be greater than -1/4m, so the black-hole-connected regionis stable in physicist' viewpoint; (2) On the contrary, in the mathematicians' viewpoint, the existence of the real frequencies means that the stable problem is unsolved by the linear perturbation method in the black-hole-connected region.