In the Linux kernel, the following vulnerability has been resolved: m68k: nfcon: Do not call console_is_registered() in nfcon_device() Since 7c2af0f634f1 ("tty: tty_io: use console_list_lock for list synchronization") show_cons_active() calls the .device() method under the console_list_lock, but console_is_registered() tries to acquire console_list_lock as well, causing a deadlock. It should not be necessary to check console_is_registered() here since the function should not be called in the fist place when the console is not registered.
m68k: nfcon: Do not call console_is_registered() in nfcon_device()