Re: [PATCH 1/1] Force mkiss to reset the line discipline when serial device is removed

[Ralf Baechle <ralf@linux-mips.org>]

On Thu, Oct 01, 2015 at 04:56:20AM +0200, jc@eclis.ch wrote:

> From: Jean-Christian de Rivaz <jc@eclis.ch>
> 
> Without the TTY_DRIVER_RESET_TERMIOS in the tty driver flags, the
> ax_open() is called again and a new unconfigured interface replace the
> one that was just deleted. Since this parasit interface is not linked
> to any serial device, when a packet is send the kernel will panic.
> 
> Signed-off-by: Jean-Christian de Rivaz <jc@eclis.ch>
> ---
>  drivers/net/hamradio/mkiss.c |    5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c
> index 216bfd3..788f43e 100644
> --- a/drivers/net/hamradio/mkiss.c
> +++ b/drivers/net/hamradio/mkiss.c
> @@ -612,6 +612,11 @@ static int ax_open(struct net_device *dev)
>  
>  	ax->flags   &= (1 << AXF_INUSE);      /* Clear ESCAPE & ERROR flags */
>  
> +	/* Will force N_TTY discipline in tty_ldisc_hangup() to avoid
> +	 * tty_ldisc_reinit() call ax_open() again when the serial
> +	 * device is removed */
> +	ax->tty->driver->flags |= TTY_DRIVER_RESET_TERMIOS;

TTY_DRIVER_RESET_TERMIOS is a flag for use by the device driver so I don't
think this is ok.

  Ralf