-current sources as of Nov 30:

 panic: pmap_page_protect !PG_V: ctx 0, va 0xf0173000, pte 0x0
Stopped at      _Debugger+0x4:  jmpl            [%o7 + 0x8], %g0
Frame pointer is at 0xf18e6c00
Call traceback:
  pc = 0xf01075a0  args = (0x0, 0x11000fe1, 0xf0137400, 0xf18e6c80, 0xf18e6d18, 0x1, 0xf18e6c68) fp = 0xf18e6c68
  pc = 0xf0033c6c  args = (0x100, 0x0, 0x1, 0xf0002000, 0x0, 0x20, 0xf18e6cd0) fp = 0xf18e6cd0
  pc = 0xf010c278  args = (0xf010bfc8, 0x100, 0xf0173000, 0x0, 0x30000000, 0x0, 0xf18e6d38) fp = 0xf18e6d38
  pc = 0xf00e24d8  args = (0xf013c2f0, 0x28, 0xf0187980, 0xf0187980, 0x0, 0xf013c400, 0xf18e6db0) fp = 0xf18e6db0
  pc = 0xf00e2404  args = (0xf01b47a0, 0xf0646800, 0x51, 0xf0181e60, 0x0, 0xf013c400, 0xf18e6e18) fp = 0xf18e6e18
  pc = 0xf00e2874  args = (0x55, 0x3f, 0x408, 0xfffffffe, 0xffffffff, 0x3, 0xf18e6e80) fp = 0xf18e6e80
  pc = 0xf00224e0  args = (0xf00224b3, 0xf05f2ae2, 0xffffffff, 0xf0142bf0, 0x0, 0x0, 0xf18e6ee8) fp = 0xf18e6ee8
  pc = 0xf0007c78  args = (0xf05f2a00, 0xf18e5300, 0xf0049d88, 0xf05d8480, 0xffffffff, 0x10, 0xf18e6f50) fp = 0xf18e6f50
  pc = 0x0  args = (0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0) fp = 0x0

Under (moderate) load compiling over NFS, with MFS?