How to fix kernel paging request error on raspberry pi miner?

Question

I'm mining Bitcoin and Litecoin using Gridseeds.

As a host/controller I'm running a Raspberry Pi with ArchLinuxARM.

I'm using the latest Arch image and compiled cgminer from this github repository:

https://github.com/girnyau/cgminer-gc3355

I'm running 10 Gridseeds. They are running well at 3.6 MH/s Scrypt (10x 360kH/s @ 850 MHz) until some point when it goes Oops:

[ 4565.377848] Unable to handle kernel paging request at virtual address 00002055
[ 4565.385255] pgd = c9df8000
[ 4565.393214] [00002055] *pgd=c9df8000, *pte=00000000, *ppte=00000000
[ 4565.404992] Internal error: Oops: 17 [#1] PREEMT ARM

Here is a screenshot:

Why? And how to fix this?

Answer 1

Ok, I found the solution here and here:

You have to enable SLUB debugging for your linux kernel. Therefore you have to edit your linux kernel command line:

sudo nano /boot/cmdline.txt

Add the following code at the end of the first line (on the same line as the other text, don't add new line!).

slub_debug=FP

Save the file then reboot your Raspberry Pi.

What the above does is basically enable some kernel debug mode on the Raspberry Pi. The mentioned kernel paging request error seems to be a kernel bug and gets caught by the debugging settings.

The downside is that the overall performance of the raspi is lower. But that does not affect the mining performance at all.