Commit crash/segfault(?) info to disk before reboot?

In the midst of screwing around with tunables I’ve stumbled across one (zvol_use_blk_mq=1) where any significant load will consistently crash/reboot my SCALE installation without warning. I’m not here for help diagnosing that. Yet.

I do need help getting this kernel panic or segfault or whatever committed to disk prior to the bounce.

I’ve downloaded a “Save Debug” from the advanced screen and I’ve looked at every file. No stack traces, no crash dump files, nada. kern.log is clean. It’s as if someone came along and yanked the power cord.

panic=0 on the kernel commandline has no impact. I was watching the local console during the hang/reboot – nothing gets displayed.

How does one typically approach this kind of problem?