From: Alan Cox <alan@linux.intel.com>
Date: Wed, 19 Sep 2012 14:34:47 +0000 (+0100)
Subject: pty: Fix locking bug on error path
X-Git-Tag: Ubuntu-snapdragon-4.4.0-1050.54~13995^2~27
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=05fb79e45ee28b97a7cb74bd5ea3a88a8d13db1c;p=mirror_ubuntu-artful-kernel.git

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 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;
 }