From 21622939fc452c7fb739464b8e49368c3ceaa0ee Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Mon, 11 Mar 2013 16:44:21 -0400 Subject: tty: Add diagnostic for halted line discipline Flip buffer work must not be scheduled by the line discipline after the line discipline has been halted; issue warning. Note: drivers can still schedule flip buffer work. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_tty.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/tty/n_tty.c') diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 68865d9..16793ec 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -153,6 +153,12 @@ static void n_tty_set_room(struct tty_struct *tty) if (left && !old_left) { WARN_RATELIMIT(tty->port->itty == NULL, "scheduling with invalid itty\n"); + /* see if ldisc has been killed - if so, this means that + * even though the ldisc has been halted and ->buf.work + * cancelled, ->buf.work is about to be rescheduled + */ + WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), + "scheduling buffer work for halted ldisc\n"); schedule_work(&tty->port->buf.work); } } @@ -1624,6 +1630,8 @@ static int n_tty_open(struct tty_struct *tty) goto err_free_bufs; tty->disc_data = ldata; + /* indicate buffer work may resume */ + clear_bit(TTY_LDISC_HALTED, &tty->flags); reset_buffer_flags(tty); tty_unthrottle(tty); ldata->column = 0; -- cgit v1.1