Commit c44ed568 authored Jun 22, 2015 by Dave Airlie Committed by Sasha Levin Jul 05, 2015

drm/dp/mst: take lock around looking up the branch device on hpd irq



[ Upstream commit 9eb1e57f564d4e6e10991402726cc83fe0b9172f ]

If we are doing an MST transaction and we've gotten HPD and we
lookup the device from the incoming msg, we should take the mgr
lock around it, so that mst_primary and mstb->ports are valid.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

parent 0e266aad

drivers/gpu/drm/drm_dp_mst_topology.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -1152,6 +1152,8 @@ static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_
		struct drm_dp_mst_port *port;
		int i;
		/* find the port by iterating down */

		mutex_lock(&mgr->lock);
		mstb = mgr->mst_primary;

		for (i = 0; i < lct - 1; i++) {
		@@ -1171,6 +1173,7 @@ static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_
		}
		}
		kref_get(&mstb->kref);
		mutex_unlock(&mgr->lock);
		return mstb;
		}