From 7f8b3987da54cb4d41ad2545cd4d7958b9a36bdf Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Wed, 19 Jul 2017 14:43:29 +0300 Subject: [PATCH] drm/mst: Avoid dereferencing a NULL mstb in drm_dp_mst_handle_up_req() In case of an unknown broadcast message is sent mstb will remain unset, so check for this. Cc: Dave Airlie Cc: Lyude Cc: Daniel Vetter Signed-off-by: Imre Deak Reviewed-by: Lyude Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20170719114330.26540-3-imre.deak@intel.com --- drivers/gpu/drm/drm_dp_mst_topology.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index ce0e584..7a62011 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2324,7 +2324,9 @@ static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr) DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn); } - drm_dp_put_mst_branch_device(mstb); + if (mstb) + drm_dp_put_mst_branch_device(mstb); + memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx)); } return ret; -- 2.7.4