I have the same GPU, and have also started experiencing system hangs since the
past 1-2 months. I believe it may be related to this issue, since it only
occurs when using 3D graphics in some form, either while playing Left 4 Dead 2
or when using the Chromium browser with GPU acceleration enabled. In the case
of Left 4 Dead 2, the system always hangs unpredictably at some point.

I am using the AMDGPU driver, with AMDGPU CIK support enabled.

I tried running 4.13 stable today, and the crash still occurred. I will try
older kernels to see if I am still able to reproduce.