From: Imre Deak Date: Wed, 19 Jul 2017 11:43:29 +0000 (+0300) Subject: drm/mst: Avoid dereferencing a NULL mstb in drm_dp_mst_handle_up_req() X-Git-Tag: MMI-PSA29.97-13-9~4623^2^2~23 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=7f8b3987da54cb4d41ad2545cd4d7958b9a36bdf;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git 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 --- diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index ce0e58442939..7a6201133eb9 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;