Crash when selecting GPU or clicking System in settings with RX5700XT Blender was working fine for me recently, but now I'm observing a problem.
Blender 2.81a and 2.79 seem to have the same issue. using cycles I get a crash as soon as I select GPU from the list of rendering devices. I don't even start rendering, it crashes just by selecting GPU. I went to check settings (do not recall if its set to GPU or GPU+CPU) only to find that clicking the System tab in settings also causes an instant crash. The computer is updated regularly, but I don't know when the issue showed up. How can I troubleshoot this?

on the console the only piece of information it seems to give me is "segmentation fault"

OS is Ubuntu 18.04LTS
In the event that it helps someone else out, I think the issue was an incompatibility with a kernel update. It's unfortunate but it appears that AMDGPU lags behind Ubuntu in kernel compatibility.

The machine recently updated to Kernel version 5.3. reverted it to 5.0 which was the previous version, reinstalled amdgpu and everything is fine again.
I installed amdgpu (pro version this time) 19.50, which is the latest version as of Jan 2020.