syzkaller found a bug in tty_43.c which i noticed could lock up my system after i wrote a reproducer for it.
i was curious why 43bsd compat is enabled by default on amd64 then noticed it gets loaded by tty if it detects an unrecognized ioctl https://github.com/NetBSD/src/blob/trunk/sys/kern/tty.c#L1420 this seems to be a strange choice, especially on archs that never ran 43bsd binaries. were applications relying on these ioctls more recently? i'm not familiar with the history of this code, but maybe someone here is
