| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.12 169/196] drm/mst: Avoid dereferencing a NULL mstb in drm_dp_mst_handle_up_req() | Date | Tue, 25 Jul 2017 12:22:48 -0700 |
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4.12-stable review patch. If anyone has any objections, please let me know.
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From: Imre Deak <imre.deak@intel.com>
commit 7f8b3987da54cb4d41ad2545cd4d7958b9a36bdf upstream.
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> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20170719114330.26540-3-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/gpu/drm/drm_dp_mst_topology.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- 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(stru 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;
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