De10-nano kernel panic

I have a kernel build according to this tutorial.

I got the following error message.

[    2.117450] 8<--- cut here ---                                                                                                                              [104/1236]
[    2.120498] Unhandled fault: imprecise external abort (0x406) at 0xbc9a8cd6                                                                                           
[    2.127434] pgd = (ptrval)                                                                                                                                            
[    2.130132] [bc9a8cd6] *pgd=00000000                                                                                                                                  
[    2.133703] Internal error: : 406 [#1] SMP ARM
[    2.138134] Modules linked in:                                                                                                                                        
[    2.141181] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.15.50-altera #1                                                                                               
[    2.147774] Hardware name: Altera SOCFPGA                         

I can put more of the messages in here. I didn’t know how much is good.

I have to few experience with the linux kernel and no clue where to get the right infos to debug it myself. If you have also good material to learn embedded linux, that would help too.

If you have any info what this info means, I’d be very thankful.