Re: PROBLEM: kernel NULL pointer dereference when yanking ftdi usb-serial during BREAK

[Johan Hovold]

On Wed, Jun 07, 2023 at 10:20:31PM -0400, Nick Bowler wrote:

> I just hit an oops when unplugging my usb serial adapter.  So naturally,
> I tried it again, and found if I use minicom to send BREAK and then
> quickly yank the cable, I can reliably cause this oops every single
> time.

Well, don't do that then. ;)

I ran into this a couple of years ago myself but ended up preempted
before I could finish the fix I was working on.

The problem is that the tty layer happily calls back into the driver to
disable the break state after the device is gone.

Something like the below fixes it. I'll revisit this in a couple of
weeks.

Johan