From 6d27a63caad3f13e96cf065d2d96828c2006be6b Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 10 Jan 2016 22:40:56 -0800 Subject: [PATCH] n_tty: Fix unsafe reference to "other" ldisc Although n_tty_check_unthrottle() has a valid ldisc reference (since the tty core gets the ldisc ref in tty_read() before calling the line discipline read() method), it does not have a valid ldisc reference to the "other" pty of a pty pair. Since getting an ldisc reference for tty->link essentially open-codes tty_wakeup(), just replace with the equivalent tty_wakeup(). Cc: Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_tty.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index d9a5fc28fef4..b280abaad91b 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -269,16 +269,13 @@ static void n_tty_check_throttle(struct tty_struct *tty) static void n_tty_check_unthrottle(struct tty_struct *tty) { - if (tty->driver->type == TTY_DRIVER_TYPE_PTY && - tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { + if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) return; if (!tty->count) return; n_tty_kick_worker(tty); - n_tty_write_wakeup(tty->link); - if (waitqueue_active(&tty->link->write_wait)) - wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); + tty_wakeup(tty->link); return; } -- 2.20.1