freebsd stable - Nov 2013 - 10.0-BETA3 Fatal trap 12 with GEOM cache, current process = 13 (g_down)

I have
FreeBSD 10.0-BETA3 #0 r257891 amd64

I use geom cache

Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address   = 0xd3a
fault code              = supervisor write data, page not present
instruction pointer     = 0x20:0xffffffff8186cfc5
stack pointer           = 0x28:0xfffffe01751d6980
frame pointer           = 0x28:0xfffffe01751d69c0
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         = 13 (g_down)
trap number             = 12
panic: page fault
cpuid = 1
KDB: stack backtrace:
#0 0xffffffff808f99f0 at kdb_backtrace+0x60
#1 0xffffffff808c0fb5 at panic+0x155
#2 0xffffffff80ce1052 at trap_fatal+0x3a2
#3 0xffffffff80ce1329 at trap_pfault+0x2c9
#4 0xffffffff80ce0ab6 at trap+0x5e6
#5 0xffffffff80cc7d52 at calltrap+0x8
#6 0xffffffff8186c958 at g_cache_start+0x258
#7 0xffffffff80828332 at g_io_schedule_down+0x3f2
#8 0xffffffff80828b2d at g_down_procbody+0x6d
#9 0xffffffff8088dc7a at fork_exit+0x9a
#10 0xffffffff80cc828e at fork_trampoline+0xe
Uptime: 7h39m45s
...
#0  doadump (textdump=<value optimized out>) at pcpu.h:219
219     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) #0  doadump (textdump=<value optimized out>) at pcpu.h:219
#1  0xffffffff808c0c30 in kern_reboot (howto=260)
    at /usr/src/sys/kern/kern_shutdown.c:447
#2  0xffffffff808c0ff4 in panic (fmt=<value optimized out>)
    at /usr/src/sys/kern/kern_shutdown.c:754
#3  0xffffffff80ce1052 in trap_fatal (frame=<value optimized out>,
    eva=<value optimized out>) at /usr/src/sys/amd64/amd64/trap.c:882
#4  0xffffffff80ce1329 in trap_pfault (frame=0xfffffe01751d68d0, usermode=0)
    at /usr/src/sys/amd64/amd64/trap.c:699
#5  0xffffffff80ce0ab6 in trap (frame=0xfffffe01751d68d0)
    at /usr/src/sys/amd64/amd64/trap.c:463
#6  0xffffffff80cc7d52 in calltrap ()
    at /usr/src/sys/amd64/amd64/exception.S:232
#7  0xffffffff8186cfc5 in g_cache_read (sc=0xfffff8000c5c2600,
    bp=0xfffff8008ddf1ba0)
    at /usr/src/sys/modules/geom/geom_cache/../../../geom/cache/g_cache.c:302
#8  0xffffffff8186c958 in g_cache_start (bp=<value optimized out>)
    at /usr/src/sys/modules/geom/geom_cache/../../../geom/cache/g_cache.c:398
#9  0xffffffff80828332 in g_io_schedule_down (tp=<value optimized out>)
    at /usr/src/sys/geom/geom_io.c:749
#10 0xffffffff80828b2d in g_down_procbody (arg=<value optimized out>)
    at /usr/src/sys/geom/geom_kern.c:111
#11 0xffffffff8088dc7a in fork_exit (
    callout=0xffffffff80828ac0 <g_down_procbody>, arg=0x0,
    frame=0xfffffe01751d6ac0) at /usr/src/sys/kern/kern_fork.c:995
#12 0xffffffff80cc828e in fork_trampoline ()
    at /usr/src/sys/amd64/amd64/exception.S:606
#13 0x0000000000000000 in ?? ()
Current language:  auto; currently minimal
(kgdb)

I can provide all the necessary information, but I need your help.

Thanks.