Crash when specifying non-existent serial port in speakup / tty_kopen

[Samuel Thibault]

Matthias Reichl, le mer. 04 nov. 2020 22:15:05 +0100, a ecrit:
> > This looks like only a warning, did it actually crash?
> 
> Yes, scroll down a bit, the null pointer oops followed almost
> immediately after that
> 
> [   49.979043] BUG: kernel NULL pointer dereference, address: 0000000000000090

Ah, [   50.102938]  tty_init_dev+0xb5/0x1d0

probably the trailing release_tty call that does

tty->port->itty = NULL;
(itty is after a struct tty_bufhead + the tty pointer, that looks
plausible).

so probably an if (tty->port) in release_tty could help?

Samuel