In the Linux kernel, the following vulnerability has been resolved: tty: tty_port: restore TTY_IO_ERROR on activation failure Make sure to restore the TTY_IO_ERROR flag if activation fails to prevent I/O attempts on a port that is gone or powered down. This specifically avoids issues like kernel panic due to unclocked accesses or NULL-pointer dereferences when accessing powered down or deregistered ports when a TTY ioctl races with hangup and open. Note that the flag is set again in tty_port_close() but not restoring it on activation failure leaves a window where drivers fail to handle the ioctl-hangup race.
https://git.kernel.org/stable/c/7021acc84c2e0add77a1a33152e3a1e428fdbfdb
https://git.kernel.org/stable/c/6388409b711eb91b14fa075a4d861ccc4df1cfe7
https://git.kernel.org/stable/c/56964f6a31238fb41d5830bb42520c5b10ff7d8f
https://git.kernel.org/stable/c/34d4f67472ef7a744970b772a8565ddc727788e2