Patch "drm: fix mutex leak in drm_dp_get_mst_branch_device" has been added to the 4.1-stable tree

This is a note to let you know that I've just added the patch titled

drm: fix mutex leak in drm_dp_get_mst_branch_device

to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drm-fix-mutex-leak-in-drm_dp_get_mst_branch_device.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Adam Richter <[email protected]>
Date: Fri, 16 Oct 2015 03:33:02 -0700
Subject: drm: fix mutex leak in drm_dp_get_mst_branch_device

From: Adam Richter <[email protected]>

commit 30730c7f5943b3beace1e29f7f1476e05de3da14 upstream.

In Linux 4.3-rc5, there is an error case in drm_dp_get_branch_device that returns without releasing mgr->lock, resulting a spew of kernel messages about a kernel work function possibly having leaked a mutex and presumably more serious adverse consequences later. This patch changes the error to "goto out" to unlock the mutex before returning.

[airlied: grabbed from drm-next as it fixes something we've seen]

---
 drivers/gpu/drm/drm_dp_mst_topology.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

@@ -1179,17 +1179,18 @@ static struct drm_dp_mst_branch *drm_dp_
 
 		list_for_each_entry(port, &mstb->ports, next) {
 			if (port->port_num == port_num) {
-				if (!port->mstb) {
+				mstb = port->mstb;
+				if (!mstb) {
 					DRM_ERROR("failed to lookup MSTB with lct %d, rad %02x\n", lct, rad[0]);
-					return NULL;
+					goto out;
 				}
 
-				mstb = port->mstb;
 				break;
 			}
 		}
 	}
 	kref_get(&mstb->kref);
+out:
 	mutex_unlock(&mgr->lock);
 	return mstb;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.1/drm-fix-mutex-leak-in-drm_dp_get_mst_branch_device.patch