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>

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 2bace84..a82b399 100644 (file)
--- 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;
 }