I'm not sure about how to locally pipe dmesg log to file so the moment when the
system freezes could be captured.

And interestingly, the GCVM_L2_PROTECTION_FAULT errors that I saw from
journalctl when it froze last time went missing somehow... maybe I mistook it,
but whenever the system froze the following lines are guaranteed to show up
(ring sdma0 timeout), so it's most likely sdma0 type.

[drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring sdma0 timeout, signaled
seq=151787, emitted seq=151789
[drm:amdgpu_job_timedout [amdgpu]] *ERROR* Process information: process Xorg
pid 1838 thread Xorg:cs0 pid 1862

Currently the system is running okay as I haven't opened Nemo yet (which can
almost 100% cause the freeze). Web browsers such as Firefox and Chrome
currently don't cause the freeze.