Commit 30730c7f authored Oct 16, 2015 by Adam Richter Committed by Dave Airlie Oct 22, 2015

drm: fix mutex leak in drm_dp_get_mst_branch_device



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]

Signed-off-by: Adam J. Richter <adam_richter2004@yahoo.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

parent 1099f860

drivers/gpu/drm/drm_dp_mst_topology.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -1194,17 +1194,18 @@ static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_

		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;
		}