From a342846f9b0448996f56ebece80454d41b431ce2 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Fri, 16 Jan 2015 15:05:35 -0500 Subject: n_tty: Fix throttle for canon lines > 3967 chars The tty driver will be mistakenly throttled if a line termination has not been received, and the line exceeds 3967 chars. Thus, it is possible for the driver to stop sending when it has not yet sent the newline. This does not apply to the pty driver. Don't throttle until at least one line termination has been received. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_tty.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/tty/n_tty.c') diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index b60b043f47d8..d4b14c30794e 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -247,6 +247,8 @@ static void n_tty_write_wakeup(struct tty_struct *tty) static void n_tty_check_throttle(struct tty_struct *tty) { + struct n_tty_data *ldata = tty->disc_data; + if (tty->driver->type == TTY_DRIVER_TYPE_PTY) return; /* @@ -254,6 +256,9 @@ static void n_tty_check_throttle(struct tty_struct *tty) * mode. We don't want to throttle the driver if we're in * canonical mode and don't have a newline yet! */ + if (ldata->icanon && ldata->canon_head == ldata->read_tail) + return; + while (1) { int throttled; tty_set_flow_change(tty, TTY_THROTTLE_SAFE); -- cgit v1.2.3-59-g8ed1b