Re: tty crash in tty_ldisc_receive_buf()

[Michael Neuling]

> > +	/* This probably shouldn't happen, but return 0 data processed */
> > +	if (!ldata)
> > +		return 0;
> > +
> > Â	while (1) {
> > Â		/*
> > Â		Â* When PARMRK is set, each input char may take up to 3
> > chars
> 
> Maybe your patch should looks like:
> +	/* This probably shouldn't happen, but return 0 data processed */
> +	if (!ldata) {
> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂup_read(&tty->termios_rwsem);
> +		return 0;
> +ÂÂÂÂÂÂÂ}

Oops, nice catch.. Thanks!

That does indeed fix the problem now without the softlockup.  I'm not sure it's
the right fix, but full patch below.

Anyone see a problem with this approach? Am I just papering over a real issue?

> Maybe below patch should work:
> @@ -1668,11 +1668,12 @@ static int
> Ân_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂchar *fp, int count, int flow)
> Â{
> -ÂÂÂÂÂÂÂstruct n_tty_data *ldata = tty->disc_data;
> +ÂÂÂÂÂÂÂstruct n_tty_data *ldata;
> 			ÂÂÂÂÂÂÂÂÂÂÂint room, n, rcvd = 0, overflow;
> 
> ÂÂÂÂÂÂÂÂdown_read(&tty->termios_rwsem);
> 
> +ÂÂÂÂÂÂÂldata = tty->disc_data;

I did try just that alone and it didn't help.

Mikey


------------------------------------------------------------------------