pty: Fix locking bug on error path

We end up dropping the mutex twice on some errors. We don't want to do
that.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 2bace847eb39..a82b39939a9c 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -628,6 +628,7 @@ static int ptmx_open(struct inode *inode, struct file *filp)
         index = devpts_new_index(inode);
         if (index < 0) {
                 retval = index;
+                mutex_unlock(&devpts_mutex);
                 goto err_file;
         }
 
@@ -667,7 +668,6 @@ out:
         mutex_unlock(&tty_mutex);
         devpts_kill_index(inode, index);
 err_file:
-        mutex_unlock(&devpts_mutex);
         tty_free_file(filp);
         return retval;
 }