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

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

From: Jiri Slaby <redacted>

commit c290f8358acaeffd8e0c551ddcc24d1206143376 upstream.

When tty_driver_lookup_tty fails in tty_open, we forget to drop a
reference to the tty driver. This was added by commit 4a2b5fddd5 (Move
tty lookup/reopen to caller).

Fix that by adding tty_driver_kref_put to the fail path.

I will refactor the code later. This is for the ease of backporting to
stable.

Introduced-in: v2.6.28-rc2
Signed-off-by: Jiri Slaby <redacted>
Cc: Alan Cox <redacted>
Acked-by: Sukadev Bhattiprolu <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/tty/tty_io.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c

@@ -1872,6 +1872,7 @@ got_driver:
 		if (IS_ERR(tty)) {
 			tty_unlock();
 			mutex_unlock(&tty_mutex);
+			tty_driver_kref_put(driver);
 			return PTR_ERR(tty);
 		}
 	}