It is wired that tty1 ~ tty6 frequently be fronzen on my Arch Linux. When this problem occurs, all the tty console（tty1 ~ tty6) display nothing but a underline cursor which is not blinking. However, I can even login into my system if I input the correct username and password. When I typing my username and password, there is nothing appear on the screen, but the login status can be checked via systemd's journal.
I really wondering why and how my tty can be stuck?