Comment # 1 on bug 1088556 from Borislav Petkov

First thing to try: update the BIOS. You have 3.30 and judging by 

http://www.asrock.com/mb/AMD/AB350%20Pro4/#BIOS

[ I'm assuming this is your board from

 Apr 07 15:14:32 linux-p51k kernel: DMI: To Be Filled By O.E.M. To Be Filled By
O.E.M./AB350 Pro4, BIOS P3.30 10/31/2017

 ]

the current one is 4.70. Page also says you need to update to 3.40 first
so make sure you read the "how to update" link.

Also, yes, remove the nvidia crap and by that I don't mean just rmmod
the driver but completely remove the sources and install a fresh,
untainted kernel.

That should be all for now.