This is a note to let you know that I've just added the patch titled
drm/mst: Avoid dereferencing a NULL mstb in drm_dp_mst_handle_up_req()
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-mst-avoid-dereferencing-a-null-mstb-in-drm_dp_mst_handle_up_req.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7f8b3987da54cb4d41ad2545cd4d7958b9a36bdf Mon Sep 17 00:00:00 2001
From: Imre Deak <imre.deak@xxxxxxxxx>
Date: Wed, 19 Jul 2017 14:43:29 +0300
Subject: drm/mst: Avoid dereferencing a NULL mstb in drm_dp_mst_handle_up_req()
From: Imre Deak <imre.deak@xxxxxxxxx>
commit 7f8b3987da54cb4d41ad2545cd4d7958b9a36bdf upstream.
In case of an unknown broadcast message is sent mstb will remain unset,
so check for this.
Cc: Dave Airlie <airlied@xxxxxxxxxx>
Cc: Lyude <lyude@xxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
Reviewed-by: Lyude <lyude@xxxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20170719114330.26540-3-imre.deak@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -2323,7 +2323,9 @@ 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;
Patches currently in stable-queue which might be from imre.deak@xxxxxxxxx are
queue-4.4/drm-mst-avoid-dereferencing-a-null-mstb-in-drm_dp_mst_handle_up_req.patch
queue-4.4/drm-mst-avoid-processing-partially-received-up-down-message-transactions.patch
queue-4.4/drm-mst-fix-error-handling-during-mst-sideband-message-reception.patch