Problems with a new Ryzen-based PC

Hi all,

It's been a while since I wrote to the list, but I'm back with a new problem.  Once again the hardware we use has reached end-of-life, and I'm left to try and get our RTAI system working on some new modern hardware.

New system:

AMD Ryzen 3 1200
Gigabyte A320M-HD2
1TB WD Blue
MSI Radeon HD 6450

Installing our usual software (Linux 4.1.18, RTAI... 5? I think) on it mostly works, except that our RT-enabled programs freeze the system (mouse and keyboard unresponsive, display frozen) on attempting to start them, and I notice during bootup where we insmod the various RTAI modules that on insmod of rtai_sched, I get a kernel bug:

BUG: unable to handle kernel paging request at 00007ffde855f1e0

Attached is a photo of the full kernel bug readout.

I tried recompiling the kernel, RTAI, and our software on the new machine to no avail.   Manually running the latency tests in the testsuite appears to work and give reasonable latencies.

Anybody have any idea where things are falling down?

-Duane Jeffery