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 <airlied@redhat.com>
Cc: Lyude <lyude@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lyude <lyude@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20170719114330.26540-3-imre.deak@intel.com
This commit is contained in:
Imre Deak 2017-07-19 14:43:29 +03:00 committed by Daniel Vetter
parent 448421b5e9
commit 7f8b3987da

View file

@ -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;