1 files changed, 12 insertions, 6 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 2caa2936d1b1..c7f8f7bc1423 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -274,7 +274,8 @@ static void n_tty_check_unthrottle(struct tty_struct *tty)
                         return;
                 n_tty_set_room(tty);
                 n_tty_write_wakeup(tty->link);
-                wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT);
+                if (waitqueue_active(&tty->link->write_wait))
+                        wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT);
                 return;
         }
 
@@ -349,7 +350,8 @@ static void n_tty_packet_mode_flush(struct tty_struct *tty)
         spin_lock_irqsave(&tty->ctrl_lock, flags);
         if (tty->link->packet) {
                 tty->ctrl_status |= TIOCPKT_FLUSHREAD;
-                wake_up_interruptible(&tty->link->read_wait);
+                if (waitqueue_active(&tty->link->read_wait))
+                        wake_up_interruptible(&tty->link->read_wait);
         }
         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 }
@@ -1155,7 +1157,8 @@ static void n_tty_receive_break(struct tty_struct *tty)
                 put_tty_queue('\0', ldata);
         }
         put_tty_queue('\0', ldata);
-        wake_up_interruptible(&tty->read_wait);
+        if (waitqueue_active(&tty->read_wait))
+                wake_up_interruptible(&tty->read_wait);
 }
 
 /**
@@ -1213,7 +1216,8 @@ static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
                 put_tty_queue('\0', ldata);
         else
                 put_tty_queue(c, ldata);
-        wake_up_interruptible(&tty->read_wait);
+        if (waitqueue_active(&tty->read_wait))
+                wake_up_interruptible(&tty->read_wait);
 }
 
 static void
@@ -1802,8 +1806,10 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
                 start_tty(tty);
 
         /* The termios change make the tty ready for I/O */
-        wake_up_interruptible(&tty->write_wait);
-        wake_up_interruptible(&tty->read_wait);
+        if (waitqueue_active(&tty->write_wait))
+                wake_up_interruptible(&tty->write_wait);
+        if (waitqueue_active(&tty->read_wait))
+                wake_up_interruptible(&tty->read_wait);
 }
 
 /**