In the Linux kernel, the following vulnerability has been resolved:

drm/dp_mst: Fix resetting msg rx state after topology removal

If the MST topology is removed during the reception of an MST down reply
or MST up request sideband message, the
drm_dp_mst_topology_mgr::up_req_recv/down_rep_recv states could be reset
from one thread via drm_dp_mst_topology_mgr_set_mst(false), racing with
the reading/parsing of the message from another thread via
drm_dp_mst_handle_down_rep() or drm_dp_mst_handle_up_req(). The race is
possible since the reader/parser doesn't hold any lock while accessing
the reception state. This in turn can lead to a memory corruption in the
reader/parser as described by commit bd2fccac61b4 ("drm/dp_mst: Fix MST
sideband message body length check").

Fix the above by resetting the message reception state if needed before
reading/parsing a message. Another solution would be to hold the
drm_dp_mst_topology_mgr::lock for the whole duration of the message
reception/parsing in drm_dp_mst_handle_down_rep() and
drm_dp_mst_handle_up_req(), however this would require a bigger change.
Since the fix is also needed for stable, opting for the simpler solution
in this patch.

https://git.kernel.org/stable/c/94b33b2d7640e807869451384eb88321dd0ffbd4

https://git.kernel.org/stable/c/a6fa67d26de385c3c7a23c1e109a0e23bfda4ec7

https://git.kernel.org/stable/c/be826b4451fd187a7c0b04be4f8243d5df6e0450

https://git.kernel.org/stable/c/d834d20d2e86c52ed5cab41763fa61e6071680ef