In the Linux kernel, the following vulnerability has been resolved:
tty: abort break signalling on hangup
The break ioctls can race with hangup and end up calling into a tty
driver for a device that is already gone or powered down.
Drivers must handle this race, but TCSBRK and TCSBRKP should still be
aborted to avoid calling back into the driver after a user-controlled
timeout (possibly even after the tty has been reopened).
Note that drivers should disable any break state on shutdown so just
return on hangup (calling break_ctl() again is racy and will most likely
fail for drivers handling the race).