From: Imre Deak <imre.deak@intel.com>
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()
References: bnc#1060662
Patch-mainline: v4.12.4
Git-commit: 7f8b3987da54cb4d41ad2545cd4d7958b9a36bdf
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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
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 025c406f2744..89cd38d254a5 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;
--
2.14.2