From: Peter Hurley <peter@hurleysoftware.com>
Date: Thu, 16 Oct 2014 19:33:28 +0000 (-0400)
Subject: pty: Hold ctrl_lock for packet mode updates
X-Git-Tag: v3.19-rc1~79^2~198
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=4ed60fc257185dbb0daea7cd3e4289d1658b11f6;p=linux.git

pty: Hold ctrl_lock for packet mode updates

Updates to the packet mode enable require holding the ctrl_lock;
the serialization prevents corruption of adjacent fields.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index bcec4c71a408..7a1a53819e22 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -47,7 +47,9 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
 	set_bit(TTY_IO_ERROR, &tty->flags);
 	wake_up_interruptible(&tty->read_wait);
 	wake_up_interruptible(&tty->write_wait);
+	spin_lock_irq(&tty->ctrl_lock);
 	tty->packet = 0;
+	spin_unlock_irq(&tty->ctrl_lock);
 	/* Review - krefs on tty_link ?? */
 	if (!tty->link)
 		return;