The issue is triggered when using the AMDGPU-PRO OpenCL driver and is related to AMDGPU DRM. To sum it up:
As a game developer, I need to test games on multiples configurations, including multiple GPUs. Especially, I want to test games I develop on hardware with lower performances and less features than my usual GPU. For that purpose I just added to my computer an old Radeon HD 3650 alongside my usual R9 390X.
On the graphic side of things, both GPU works, but on the compute side of things, OpenCL application now badly crashes.
I'm using legacy “Orca” OpenCL stack on amdgpu-pro 20.20-1089974 on Ubuntu 20.04. Everything else than OpenCL thing is using stock Ubuntu 20.04 packages: no custom kernel, no amdgpu-pro dkms module, no amdgpu-pro drm, no amdgpu-pro glx, etc.
The R9 390X uses the amdgpu driver while the HD 3650 uses the radeon driver.
This bug makes software like GIMP, Darktable, or LuxMark unable to start (they crash at startup).
Blender starts then crashes before being able to change the preferences to disable OpenCL.
LibreOffice Calc crashes at startup but fortunately intercepts the crash and disables OpenCL for subsequent runs. This still gives poor user experience since the user has to open a sheet document two times to get it loaded right.