Found the reason, but don't know why it happens.

It depends on Max_dp variable.
If it equals 5 or 4, then there's no problem. If 3, 2, or 1, it causes problem. if DP=3, then hangs on 2800 (around), if DP=2, then hangs on 280, if DP=1, then hangs on 8.

What might be the reason?