I need to clarify again as we have a "chicken and egg" problem. The fixes_for_5.8 patch at OBS describes 3 separate problems that had to be fixed to build and run VirtualBox. The problem was that if all 3 were applied, VB would fail to build under kernel 5.8 because the necessary globals were missing. Accordingly, the patch needed to handle executable module memory was commented out. You SHOULD not apply the patch from OBS as long as you install the latest version of the virtualbox-host-source package. Assuming you have a patches kernel, either one you built, or the one that Pete referenced, then you ONLY need to apply the "Patch for VB module" listed above. It only needs to uncomment the references to acquire memory. The changes in the fixes_for_5.8.patch from OBS have already been applied.