Describe CVE-2021-47362.
What is CVE-2021-47362?
In the Linux kernel, the following vulnerability has been resolved:

drm/amd/pm: Update intermediate power state for SI

Update the current state as boot state during dpm initialization.
During the subsequent initialization, set_power_state gets called to
transition to the final power state. set_power_state refers to values
from the current state and without current state populated, it could
result in NULL pointer dereference.

For ex: on platforms where PCI speed change is supported through ACPI
ATCS method, the link speed of current state needs to be queried before
deciding on changing to final power state's link speed. The logic to query
ATCS-support was broken on certain platforms. The issue became visible
when broken ATCS-support logic got fixed with commit
f9b7f3703ff9 ("drm/amdgpu/acpi: make ATPX/ATCS structures global (v2)").

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1698.