Re: [PATCH v2] tty: Fix WARNING in tty_set_termios()

[shuah]

On 1/31/19 5:14 PM, Greg KH wrote:
> On Thu, Jan 31, 2019 at 04:23:59PM -0700, Shuah Khan wrote:
> > tty_set_termios() has the following WARN_ON which can be triggered with a
> > syscall to invoke TIOCSETD __NR_ioctl.
> >
> > WARN_ON(tty->driver->type == TTY_DRIVER_TYPE_PTY &&
> >                  tty->driver->subtype == PTY_TYPE_MASTER);
> > Reference: https://syzkaller.appspot.com/bug?id=2410d22f1d8e5984217329dd0884b01d99e3e48d
> >
> > The problem started with commit 7721383f4199 ("Bluetooth: hci_uart: Support
> > operational speed during setup") which introduced a new way for how
> > tty_set_termios() could end up being called for a master pty.
> >
> > Fix the problem by preventing setting the HCI line discipline for PTYs
> > from hci_uart_setup() and hci_uart_set_flow_control().
> >
> > The reproducer is used to reproduce the problem and verify the fix.
> >
> > Reported-by: syzbot+a950165cbb86bdd023a4@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Shuah Khan <shuah@xxxxxxxxxx>
> > ---
> >   drivers/bluetooth/hci_ldisc.c | 11 +++++++++++
> >   1 file changed, 11 insertions(+)
>
> I think the subject should be something like:
> 	"bluetooth: hci: Fix warning in tty_set_termios()"
> it isn't a tty core problem :)

Yes. Sorry about that. Will get it right in my v3.

thanks,
-- Shuah