n_tty: Fix throttle for canon lines > 3967 chars (a342846f) · Commits · 戴 / test

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 <peter@hurleysoftware.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/n_tty.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -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);

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