I see a similar backtrace on 4.19.0-11706-g11743c56785c (Linus' tree mid-merge window). My system has a "fiji" card. The first kernel is 4.19 (upstream release), and the second kernel where the backtrace occurs is with 4.19+. The second kernel is kexec'd from the first. If I don't load amdgpu in the first kernel, the second kernel works. So there is something missed in the shutdown path.