I was having very similar issues with my Orange Pi+ 2E and even with all patches applied (I'm running megous' mainline kernel that includes the patch you linked) and I was still having trouble with random hangs and rcu stalls. I was able to get the machine stable by setting cpufreq to a fixed frequency. It does not matter if I set it to low or high so mine's now stable running at 1.37Ghz for days.
Did you lock yours at 1200Mhz or was it just never idle ? (Is it still stable for you?)