rebooting issue on FreeBSD 9.0-RELEASE with zfs root

gistfile1.txt

Fatal trap 12: page fault while in kernel mode
cpuid = 2; apic id = 04
fault virtual address	= 0x4a0
fault code		= supervisor read data, page not present
instruction pointer	= 0x20:0xffffffff806d958f
stack pointer	        = 0x28:0xffffff833d029a10
frame pointer	        = 0x28:0xffffff833d029a90
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 2 (arc_reclaim_thread)
trap number		= 12
panic: page fault
cpuid = 2
KDB: stack backtrace:
#0 0xffffffff8070767e at kdb_backtrace+0x5e
#1 0xffffffff806d1f67 at panic+0x187
#2 0xffffffff809238f0 at trap_fatal+0x290
#3 0xffffffff80923c39 at trap_pfault+0x1f9
#4 0xffffffff809240ff at trap+0x3df
#5 0xffffffff8090e62f at calltrap+0x8
#6 0xffffffff806d9cde at _sx_xlock+0x4e
#7 0xffffffff81117d1e at dbuf_rele+0x2e
#8 0xffffffff81116ee6 at dbuf_destroy+0x96
#9 0xffffffff8111aeb3 at dbuf_do_evict+0x53
#10 0xffffffff8110e7f4 at arc_do_user_evicts+0xb4
#11 0xffffffff81115254 at arc_reclaim_thread+0x264
#12 0xffffffff806a55df at fork_exit+0x11f
#13 0xffffffff8090eb5e at fork_trampoline+0xe
Uptime: 1d23h54m24s