Threading crash > kernel 5.10

[Steven J Abner]

Hi,
When using 8 threads vs. 4 threads, test crashes application.
AMD Ryzen 5 2400G, elementary OS 5.1.7, Ubuntu 18.04.6 LTS, System 
Stability Tester
Version 1.5.1 generic.
Testing Pi digits >= 64M with threads @ 8 will crash application, can 
not say for certain system crashes, as that occurred on different 
conditions not used on problem.
Using threads @ 4 will complete task, no crash. Also during track, used 
64M, 4,8
exclusively. Kernels 5.18, 5.15 will crash, kernels 5.10, 5.4 will not. 
Kernels
were installed by Ubuntu Mainline Kernel Installer.
Hopefully I can be of more help, I have not built a kernel from 
scratch in many of years, LFS, so for me patches to solve on my end 
could be issue?
Steve