Rediscussion of the Stability Problem of the Schwarzschild Black Hole

We use the Kruskal time coordinate T to define the initial time. By this way, the stability study naturally becomes the one connected with the two regions, i.e. the white-hole-connected region and the black-hole-connected region. The union of the two regions covers the Schwarzschild space-time (r≥2m). We also obtain the very reasonable conclusion: the white-hole-connected region is unstable and the black-hole-connected region is stable. If we take the instability with caution and seriousness, it is not unreasonable to regard that the Schwarzschild black hole might be unstable to some extent.