panic: non-current pmap 0xffffa00020eab8f0 on Rpi3

[bob prohaska]

On Tue, Oct 20, 2020 at 12:30:05PM -0400, Mark Johnston wrote:
> 
> I set up a RPi3 to try and repro this and have so far managed to trigger
> it once using Peter Holm's stress2 suite, so I'll keep investigating.  I
> hadn't configured a dump device, but I was able to confirm from DDB that
> PCPU_GET(curpmap) == &vmspace0->vm_pmap.
> 

Is the invalid pmap fault related in any way to intensity of swap usage?
That's easily adjusted using -j values building things like www/chromium.
In the past, when I've reported crashes caused by stress2 I've observed
a "that's inevitable" sort of response with some regularity. Panics when
doing more normal things like make seem to stimulate greater interest.


> For future reference,
> https://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug.html

The pieces are all in place, but the machine doesn't seem to find core
dumps when coming up after a crash. It does routinely issue "no core dumps
found" during reboot, so it's looking. It it necessary to issue a dump
command from inside the debugger? 

Thanks for writing!

bob prohaska