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.
References 5
https://git.kernel.org/stable/c/2f8e3cad53b5c36ab0ed5d3195bfc55c59ea61a5
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/7d3f15a664d115584fc177b5f2cfbdb3e5a50d60
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/be98f92fc244688a6bdecbc834cf2cd243056d9d
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/d73441232f1f067eb659e94447b1353c16609711
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/e5e11274b5512e24a346ed83f8dd85e3389d2f4b
416baaa9-dc9f-4396-8d5f-8c081fb06d67