Debugging linux crashes

[Bruce Labitt]

I am experiencing severe Linux crashes, due to some unknown causes.  
They appear to be related to the use of Ty Commander and programming a 
Teensy 4.1 in the Arduino IDE environment, but I am not positive.  All I 
know at the moment, is that the screen freezes and is unresponsive to 
keyboard or mouse inputs.  The freeze lasts about 10 seconds and the 
laptop computer simply powers off.  The error seems to be quite 
repeatable.  It may or may not have started after a Nvidia graphics 
update.  I do know after a normal system update in Ubuntu 20.04 on May 
26, my system has been subject to this problem.

I have purged nvidia drivers and reinstalled them.  Didn't matter.  
Syslog and journalctl really didn't seem to show anything interesting, 
at least to my unsophisticated gaze.  Have been a wits end.  In the 
interim, I moved a lot of my "life" off the laptop onto an RPI4B-8GB 
running Raspberry Pi OS 64 bits.  Been a difficult transition, 
recovering my capabilities, computing-wise.

I backed up my whole laptop, and decided, perhaps insanely, to do a 
fresh install of Pop-OS 22.04.  With the base install, I ran into the 
same darn wifi issue that initially plagued me with this laptop.  After 
2 days of seaching, I found the answer to the slow and constantly 
rebooting iwlwifi card was to set powersave =2, which for some darned 
reason means powersave is off!  I am amazed that this issue still exists 
this day and age, I found mentions of it over all Linux distros.  The 
issue is the wrong microcode is being sent to the wifi adapter, and the 
adapter kernel panics when it receives illegal commands from the Linux 
OS.  You can see it in the syslog very clearly.  I changed the powersave 
to 2, and the wifi adapter seemingly works fine now.  This is the Intel 
WiFi 6 AX200/AX201.

Anyways, even with this brand new installation, and fixed wifi, my 
computer crashes with the combination of Arduino IDE 1.8.19, Teensyduino 
1.56, and Ty Commander 0.9.7.

However, I found that if I use Arduino IDE, and Teensyduino 1.56 only, I 
have been able to program my Teensy 4.1 without crashing. Unfortunately, 
I'd like to use Ty Commander to enable multiple Teensy's to be debugged.

I'm looking for some suggestions on how to proceed.

Is there a way to get or retain more information on system crashes?  I 
don't even know the true cause of the crash yet.  For some reason, I am 
having difficulty opening the kernel log.  Is it a text file?  Or do I 
need a special viewer?  I can open the syslog without issue.  In Pop OS 
I don't see multiple or older versions of logs.  I don't know why.  
Often older logs have a .0 or .1 extension.  The log I want to see is 
not the one created after the boot following the crash, it is the one 
before!

I'm not sure I really have the skills to deal with linux-crashdump.  I 
haven't seen a step by step procedure that I feel comfortable enough to 
proceed with.  The references use a lot of words, re: fiddling with 
grub, not so many pictures, and I don't want to really go there without 
a really complete script. Is this the path I need to take?

I could compile Ty Commander with debug binaries, I just need to type 
out:  cmake -DCMAKE_BUILD_TYPE=Debug ../..

Can I run Ty Commander with valgrind, or something like that would 
prevent yet another total crash, but perhaps capture something useful?