1 files changed, 30 insertions, 16 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index c9c27f69e101..b09023b07169 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -343,8 +343,7 @@ static void n_tty_packet_mode_flush(struct tty_struct *tty)
 		spin_lock_irqsave(&tty->ctrl_lock, flags);
 		tty->ctrl_status |= TIOCPKT_FLUSHREAD;
 		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-		if (waitqueue_active(&tty->link->read_wait))
-			wake_up_interruptible(&tty->link->read_wait);
+		wake_up_interruptible(&tty->link->read_wait);
 	}
 }
 
@@ -1108,19 +1107,29 @@ static void eraser(unsigned char c, struct tty_struct *tty)
  *	Locking: ctrl_lock
  */
 
-static void isig(int sig, struct tty_struct *tty)
+static void __isig(int sig, struct tty_struct *tty)
 {
-	struct n_tty_data *ldata = tty->disc_data;
 	struct pid *tty_pgrp = tty_get_pgrp(tty);
 	if (tty_pgrp) {
 		kill_pgrp(tty_pgrp, sig, 1);
 		put_pid(tty_pgrp);
 	}
+}
+
+static void isig(int sig, struct tty_struct *tty)
+{
+	struct n_tty_data *ldata = tty->disc_data;
+
+	if (L_NOFLSH(tty)) {
+		/* signal only */
+		__isig(sig, tty);
 
-	if (!L_NOFLSH(tty)) {
+	} else { /* signal and flush */
 		up_read(&tty->termios_rwsem);
 		down_write(&tty->termios_rwsem);
 
+		__isig(sig, tty);
+
 		/* clear echo buffer */
 		mutex_lock(&ldata->output_lock);
 		ldata->echo_head = ldata->echo_tail = 0;
@@ -1372,8 +1381,7 @@ handle_newline:
 			put_tty_queue(c, ldata);
 			smp_store_release(&ldata->canon_head, ldata->read_head);
 			kill_fasync(&tty->fasync, SIGIO, POLL_IN);
-			if (waitqueue_active(&tty->read_wait))
-				wake_up_interruptible_poll(&tty->read_wait, POLLIN);
+			wake_up_interruptible_poll(&tty->read_wait, POLLIN);
 			return 0;
 		}
 	}
@@ -1657,8 +1665,7 @@ static void __receive_buf(struct tty_struct *tty, const unsigned char *cp,
 
 	if ((read_cnt(ldata) >= ldata->minimum_to_wake) || L_EXTPROC(tty)) {
 		kill_fasync(&tty->fasync, SIGIO, POLL_IN);
-		if (waitqueue_active(&tty->read_wait))
-			wake_up_interruptible_poll(&tty->read_wait, POLLIN);
+		wake_up_interruptible_poll(&tty->read_wait, POLLIN);
 	}
 }
 
@@ -1877,10 +1884,8 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
 	}
 
 	/* The termios change make the tty ready for I/O */
-	if (waitqueue_active(&tty->write_wait))
-		wake_up_interruptible(&tty->write_wait);
-	if (waitqueue_active(&tty->read_wait))
-		wake_up_interruptible(&tty->read_wait);
+	wake_up_interruptible(&tty->write_wait);
+	wake_up_interruptible(&tty->read_wait);
 }
 
 /**
@@ -2137,6 +2142,8 @@ extern ssize_t redirected_tty_write(struct file *, const char __user *,
 
 static int job_control(struct tty_struct *tty, struct file *file)
 {
+	struct pid *pgrp;
+
 	/* Job control check -- must be done at start and after
 	   every sleep (POSIX.1 7.1.1.4). */
 	/* NOTE: not yet done after every sleep pending a thorough
@@ -2146,18 +2153,25 @@ static int job_control(struct tty_struct *tty, struct file *file)
 	    current->signal->tty != tty)
 		return 0;
 
+	rcu_read_lock();
+	pgrp = task_pgrp(current);
+
 	spin_lock_irq(&tty->ctrl_lock);
 	if (!tty->pgrp)
 		printk(KERN_ERR "n_tty_read: no tty->pgrp!\n");
-	else if (task_pgrp(current) != tty->pgrp) {
+	else if (pgrp != tty->pgrp) {
 		spin_unlock_irq(&tty->ctrl_lock);
-		if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned())
+		if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) {
+			rcu_read_unlock();
 			return -EIO;
-		kill_pgrp(task_pgrp(current), SIGTTIN, 1);
+		}
+		kill_pgrp(pgrp, SIGTTIN, 1);
+		rcu_read_unlock();
 		set_thread_flag(TIF_SIGPENDING);
 		return -ERESTARTSYS;
 	}
 	spin_unlock_irq(&tty->ctrl_lock);
+	rcu_read_unlock();
 	return 0;
 }