1 files changed, 31 insertions, 13 deletions

diff --git a/drivers/tty/tty_jobctrl.c b/drivers/tty/tty_jobctrl.c
index e7032309ee87..b71e61e79c5a 100644
--- a/drivers/tty/tty_jobctrl.c
+++ b/drivers/tty/tty_jobctrl.c
@@ -102,8 +102,8 @@ static void __proc_set_tty(struct tty_struct *tty)
 	put_pid(tty->session);
 	put_pid(tty->pgrp);
 	tty->pgrp = get_pid(task_pgrp(current));
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 	tty->session = get_pid(task_session(current));
+	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 	if (current->signal->tty) {
 		tty_debug(tty, "current tty %s not NULL!!\n",
 			  current->signal->tty->name);
@@ -292,20 +292,23 @@ void disassociate_ctty(int on_exit)
 	spin_lock_irq(&current->sighand->siglock);
 	put_pid(current->signal->tty_old_pgrp);
 	current->signal->tty_old_pgrp = NULL;
-
 	tty = tty_kref_get(current->signal->tty);
+	spin_unlock_irq(&current->sighand->siglock);
+
 	if (tty) {
 		unsigned long flags;
+
+		tty_lock(tty);
 		spin_lock_irqsave(&tty->ctrl_lock, flags);
 		put_pid(tty->session);
 		put_pid(tty->pgrp);
 		tty->session = NULL;
 		tty->pgrp = NULL;
 		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+		tty_unlock(tty);
 		tty_kref_put(tty);
 	}
 
-	spin_unlock_irq(&current->sighand->siglock);
 	/* Now clear signal->tty under the lock */
 	read_lock(&tasklist_lock);
 	session_clear_tty(task_session(current));
@@ -476,14 +479,19 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
 		return -ENOTTY;
 	if (retval)
 		return retval;
-	if (!current->signal->tty ||
-	    (current->signal->tty != real_tty) ||
-	    (real_tty->session != task_session(current)))
-		return -ENOTTY;
+
 	if (get_user(pgrp_nr, p))
 		return -EFAULT;
 	if (pgrp_nr < 0)
 		return -EINVAL;
+
+	spin_lock_irq(&real_tty->ctrl_lock);
+	if (!current->signal->tty ||
+	    (current->signal->tty != real_tty) ||
+	    (real_tty->session != task_session(current))) {
+		retval = -ENOTTY;
+		goto out_unlock_ctrl;
+	}
 	rcu_read_lock();
 	pgrp = find_vpid(pgrp_nr);
 	retval = -ESRCH;
@@ -493,12 +501,12 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
 	if (session_of_pgrp(pgrp) != task_session(current))
 		goto out_unlock;
 	retval = 0;
-	spin_lock_irq(&tty->ctrl_lock);
 	put_pid(real_tty->pgrp);
 	real_tty->pgrp = get_pid(pgrp);
-	spin_unlock_irq(&tty->ctrl_lock);
 out_unlock:
 	rcu_read_unlock();
+out_unlock_ctrl:
+	spin_unlock_irq(&real_tty->ctrl_lock);
 	return retval;
 }
 
@@ -510,20 +518,30 @@ out_unlock:
  *
  *	Obtain the session id of the tty. If there is no session
  *	return an error.
- *
- *	Locking: none. Reference to current->signal->tty is safe.
  */
 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
 {
+	unsigned long flags;
+	pid_t sid;
+
 	/*
 	 * (tty == real_tty) is a cheap way of
 	 * testing if the tty is NOT a master pty.
 	*/
 	if (tty == real_tty && current->signal->tty != real_tty)
 		return -ENOTTY;
+
+	spin_lock_irqsave(&real_tty->ctrl_lock, flags);
 	if (!real_tty->session)
-		return -ENOTTY;
-	return put_user(pid_vnr(real_tty->session), p);
+		goto err;
+	sid = pid_vnr(real_tty->session);
+	spin_unlock_irqrestore(&real_tty->ctrl_lock, flags);
+
+	return put_user(sid, p);
+
+err:
+	spin_unlock_irqrestore(&real_tty->ctrl_lock, flags);
+	return -ENOTTY;
 }
 
 /*