The module is not auto-loaded on sparc64 when a request
is made to perform an nfsd system call.
The bug appears to be in the sparc64 32-bit syscall compat
layer. I will work on a fix and see why it is not
performing the module load via kmod as it should.
Seems to be working in 5.9.8 build, perhaps it was a module
conf problem or similar. I will re-open this if I see it