10-STABLE r266808 crash

[Slawa Olhovchenkov]

  Magic: FreeBSD Kernel Dump
  Version String: FreeBSD 10.0-STABLE #0 r266808: Wed May 28 19:13:24 MSK 2014
    root at inter.trade.spb.ru:/usr/obj/usr/src/sys/TRADE
  Panic String: __lockmgr_args: downgrade a recursed lockmgr zfs @ /usr/src/sys/modules/unionfs/../../fs/unionfs/union_vnops.c:1906

  Dump Parity: 1636454732
  Bounds: 1
  Dump Status: good


I have core.txt.1 and vmcore.1.
I can run gdb on it or put on http server.