[minicoredumper] stack detection fails with kernel >= v5.18

[Holger Brunck]

Hi all,
I currently try to integrate the minicoredumper into our embedded SW. I am using 
the latest version 2.06. With kernel 5.4.x it works pretty well. But with boards using 
kernel 6.1.x I saw problems. The stacks were missing in the generated core file  
from the minicoredumper.
Our application is multithreaded and minicoredumper reports when processing the 
core file:
Aug 15 08:18:45 unit user.err minicoredumper: unable to find thread #14's (386) stack 
Aug 15 08:18:45 unit user.err minicoredumper: unable to find thread #15's (387) stack 
Aug 15 08:18:45 unit user.err minicoredumper: unable to find thread #16's (388) stack
Aug 15 08:18:45 unit user.err minicoredumper: unable to find thread #17's (389) stack

I was able to reproduce this problem in a x86 qemu environment with a mainline kernel
and parts of our application code. After bisecting the kernel I saw that this was 
introduced with kernel v5.15 due to the following commit:
7b1b610f  coredump:  Don't perform any cleanups before dumping core

Btw when using the regular core file gdb is able to show the stacks from the threads as 
expected.

Any ideas what might be the problem in the minicoredumper so that the stacks can't be 
detected properly anymore? Are there any ideas how to fix this?

Best regards
Holger Brunck