port-arm/51355: arm MP unusable

[martin%NetBSD.org@localhost]

>Number:         51355
>Category:       port-arm
>Synopsis:       arm MP unusable
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    port-arm-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jul 23 16:55:00 +0000 2016
>Originator:     Martin Husemann
>Release:        NetBSD 7.99.34
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD space-truckin.duskware.de 7.99.34 NetBSD 7.99.34 (CUBIETRUCK) #278: Sat Jul 23 18:38:29 CEST 2016 martin%night-owl.duskware.de@localhost:/usr/src/sys/arch/evbarm/compile/CUBIETRUCK evbarm
Architecture: earmv7hfeb
Machine: evbarm
>Description:

evbarm SMP machines are mostly unusable in -current, putting a tiny bit of
load on the system makes the kernel crash.

I have seen different panics:

kernel diagnostic assertion "pmap_tlb_intersecting_active_p(PAI_PMAP(pai, ti), ti)" failed: file "../../../../uvm/pmap/pmap_tlb.c", line 220 
kernel diagnostic assertion "ok" failed: file "../../../../arch/arm/arm32/pmap.c", line 1314 

unfortunately neither crash nor gdb offer a backtrace (?!)

>How-To-Repeat:

cd /usr/tests && atf-run|atf-report

>Fix:
n/a