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Commit 9eb1e57f authored by Dave Airlie's avatar Dave Airlie
Browse files

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



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: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 9254ec49

drivers/gpu/drm/drm_dp_mst_topology.c

+3 −0
Original line number Diff line number Diff line
@@ -1163,6 +1163,8 @@ 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++) {
@@ -1182,6 +1184,7 @@ 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;

}