From: Peter Hurley Date: Fri, 16 Jan 2015 20:05:35 +0000 (-0500) Subject: n_tty: Fix throttle for canon lines > 3967 chars X-Git-Tag: v4.0-rc1~81^2~32 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=a342846f9b0448996f56ebece80454d41b431ce2;p=linux.git 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 --- 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);