Commit 171f90d4 authored Sep 18, 2018 by Dmitry Safonov Committed by Greg Kroah-Hartman Oct 13, 2018

tty: Drop tty->count on tty_reopen() failure



commit fe32416790093b31364c08395727de17ec96ace1 upstream.

In case of tty_ldisc_reinit() failure, tty->count should be decremented
back, otherwise we will never release_tty().
Tetsuo reported that it fixes noisy warnings on tty release like:
  pts pts4033: tty_release: tty->count(10529) != (#fd's(7) + #kopen's(0))

Fixes: commit 892d1fa7 ("tty: Destroy ldisc instance on hangup")

Cc: stable@vger.kernel.org # v4.6+
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Reviewed-by: Jiri Slaby <jslaby@suse.cz>
Tested-by: Jiri Slaby <jslaby@suse.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent c92e73b1

drivers/tty/tty_io.c

+8 −3

Original line number	Original line	Diff line number	Diff line
	@@ -1254,6 +1254,7 @@ static void tty_driver_remove_tty(struct tty_driver driver, struct tty_struct
	static int tty_reopen(struct tty_struct *tty)		static int tty_reopen(struct tty_struct *tty)
	{		{
	struct tty_driver *driver = tty->driver;		struct tty_driver *driver = tty->driver;
			int retval;

	if (driver->type == TTY_DRIVER_TYPE_PTY &&		if (driver->type == TTY_DRIVER_TYPE_PTY &&
	driver->subtype == PTY_TYPE_MASTER)		driver->subtype == PTY_TYPE_MASTER)
	@@ -1267,10 +1268,14 @@ static int tty_reopen(struct tty_struct *tty)

	tty->count++;		tty->count++;

	if (!tty->ldisc)		if (tty->ldisc)
	return tty_ldisc_reinit(tty, tty->termios.c_line);

	return 0;		return 0;

			retval = tty_ldisc_reinit(tty, tty->termios.c_line);
			if (retval)
			tty->count--;

			return retval;
	}		}

	/**		/**