[PATCH 4.4 49/56] Bluetooth: hci_bcm: add missing tty-device sanity check

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@xxxxxxxxxx>

commit 95065a61e9bf25fb85295127fba893200c2bbbd8 upstream.

Make sure to check the tty-device pointer before looking up the sibling
platform device to avoid dereferencing a NULL-pointer when the tty is
one end of a Unix98 pty.

Fixes: 0395ffc1ee05 ("Bluetooth: hci_bcm: Add PM for BCM devices")
Cc: Frederic Danis <frederic.danis@xxxxxxxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/bluetooth/hci_bcm.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/bluetooth/hci_bcm.c
+++ b/drivers/bluetooth/hci_bcm.c
@@ -287,6 +287,9 @@ static int bcm_open(struct hci_uart *hu)
 
 	hu->priv = bcm;
 
+	if (!hu->tty->dev)
+		goto out;
+
 	mutex_lock(&bcm_device_lock);
 	list_for_each(p, &bcm_device_list) {
 		struct bcm_device *dev = list_entry(p, struct bcm_device, list);
@@ -307,7 +310,7 @@ static int bcm_open(struct hci_uart *hu)
 	}
 
 	mutex_unlock(&bcm_device_lock);
-
+out:
 	return 0;
 }