panic: non-current pmap 0xffffa00020eab8f0 on Rpi3

Still seeing non-current pmap panics on the Pi3, this time a B+ running
13.0-CURRENT (GENERIC-MMCCAM) #0 71e02448ffb-c271826(master)
during a -j4 buildworld.  The backtrace reports

panic: non-current pmap 0xffffa00020eab8f0
cpuid = 0
time = 1601947137
KDB: stack backtrace:
db_trace_self() at db_trace_self_wrapper+0x30
	 pc = 0xffff00000072999c  lr = 0xffff00000019ec8c
	 sp = 0xffff00005d96c230  fp = 0xffff00005d96c430

db_trace_self_wrapper() at kdb_backtrace+0x38
	 pc = 0xffff00000019ec8c  lr = 0xffff0000004b4984
	 sp = 0xffff00005d96c440  fp = 0xffff00005d96c500

kdb_backtrace() at vpanic+0x19c
	 pc = 0xffff0000004b4984  lr = 0xffff0000004734c0
	 sp = 0xffff00005d96c510  fp = 0xffff00005d96c560

vpanic() at panic+0x44
	 pc = 0xffff0000004734c0  lr = 0xffff0000004730dc
	 sp = 0xffff00005d96c570  fp = 0xffff00005d96c620

panic() at pmap_remove_pages+0x5d8
	 pc = 0xffff0000004730dc  lr = 0xffff00000073fe58
	 sp = 0xffff00005d96c630  fp = 0xffff00005d96c690

pmap_remove_pages() at vmspace_exit+0xb0
	 pc = 0xffff00000073fe58  lr = 0xffff0000006c77a0
	 sp = 0xffff00005d96c6a0  fp = 0xffff00005d96c700

vmspace_exit() at exit1+0x470
	 pc = 0xffff0000006c77a0  lr = 0xffff00000042e5bc
	 sp = 0xffff00005d96c710  fp = 0xffff00005d96c760

exit1() at sys_sys_exit+0x10
	 pc = 0xffff00000042e5bc  lr = 0xffff00000042e148
	 sp = 0xffff00005d96c770  fp = 0xffff00005d96c7c0

sys_sys_exit() at syscallenter+0x104
	 pc = 0xffff00000042e148  lr = 0xffff0000007463dc
	 sp = 0xffff00005d96c7d0  fp = 0xffff00005d96c7d0

syscallenter() at svc_handler+0x4c
	 pc = 0xffff0000007463dc  lr = 0xffff000000745df8
	 sp = 0xffff00005d96c7e0  fp = 0xffff00005d96c810

svc_handler() at do_el0_sync+0xf0
	 pc = 0xffff000000745df8  lr = 0xffff000000745c08
	 sp = 0xffff00005d96c820  fp = 0xffff00005d96c830

do_el0_sync() at handle_el0_sync+0x90
	 pc = 0xffff000000745c08  lr = 0xffff00000072c224
	 sp = 0xffff00005d96c840  fp = 0xffff00005d96c980

handle_el0_sync() at 0x40421150
	 pc = 0xffff00000072c224  lr = 0x0000000040421150
	 sp = 0xffff00005d96c990  fp = 0x0000ffffffffd830

KDB: enter: panic
[ thread pid 2429 tid 100951 ]
Stopped at      0x403fa408
db> 

Thanks for reading,

bob prohaska