panic in pmap_enter

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

With today's -current/amd64 MP, while building userland,

panic: pmap_enter: PG_PVLIST mapping with unmanaged page pa = 0x1669c000 
(0x1669c)
fatal breakpoint trap in supervisor mode
trap type 1 code 0 rip ffffffff804c1db5 cs 8 rflags 246 cr2 7f7ffda00158 cpl 0 
rsp ffff80004f3687a0
Stopped in pid 18603.1 (sh)..

breakpoint ()
panic()
pmap_enter()
uvm_fault_internal()
trap()
uvm_fault(0xffff80004cfcca10, 0x0, 1) -> e)

MAP 0xffff80004cfcca10: [0x0->0x7f8000000000]
  #ent=17, sz=37105664, ref=1, version=31, flags=0x41
  pmap=0xffff800059e24a40(resident=49, wired=-1)

(trying to show the page just gives the same trap again..)
(This computer has nfe0 + 4GB of memory..)

Cheers,

Patrick