Re: [Call For Testing] VirtualBox for FreeBSD! take 6

i'm running r193846M (CURRENT) and virtualbox-2.2.51. i got this panic right
after starting my windows xp image which i created under virtualbox_4.tgz.
here's a bt:

Unread portion of the kernel message buffer:
acquiring duplicate lock of same type: "IPRT Spinlock"
 1st IPRT Spinlock _at_
 /usr/home/arundel/virtualbox/work/virtualbox-2.2.51r20457/src/VBox/Runtime/r0drv/freebsd/spinlock-r0drv-freebsd.c:131
 2nd IPRT Spinlock _at_
 /usr/home/arundel/virtualbox/work/virtualbox-2.2.51r20457/src/VBox/Runtime/r0drv/freebsd/spinlock-r0drv-freebsd.c:131
KDB: stack backtrace:
db_trace_self_wrapper(c07c4189,ea94fa0c,c05fa12f,c05eb97b,c07c6fc6,...) at
db_trace_self_wrapper+0x26
kdb_backtrace(c05eb97b,c07c6fc6,c14c8284,c78ec360,ea94fa68,...) at
kdb_backtrace+0x29
_witness_debugger(c07c6fc6,c14c82f6,c14c8284,83,c14c8284,...) at
_witness_debugger+0x1e
witness_checkorder(c7c17994,9,c14c8284,83,0,...) at witness_checkorder+0x452
_mtx_lock_spin_flags(c7c17994,0,c14c8284,83,ea94facc,...) at
_mtx_lock_spin_flags+0xf5
RTSpinlockAcquire(c7c17990,ea94fabc,0,0,c95b2a10,...) at
RTSpinlockAcquire+0x2c
SUPR0ObjAddRefEx(c9edd5d0,c7e8f810,0,ea94fb04,c14b8e2b,...) at
SUPR0ObjAddRefEx+0x75
SUPR0ObjAddRef(c9edd5d0,c7e8f810,4,c7e8f810,0,...) at SUPR0ObjAddRef+0x20
RTHandleTableLookupWithCtx(c95b2a10,9,4,c886a540,c7e8f810,...) at
RTHandleTableLookupWithCtx+0xcb
SUPSemEventSignal(c7e8f810,9,c07b92b7,3,c8f13240,...) at
SUPSemEventSignal+0x56
supdrvIOCtl(c028561b,c14cab20,c7e8f810,c886a540,ea94fbd4,...) at
supdrvIOCtl+0x1ce7
VBoxDrvFreeBSDIOCtl(c95b6000,c028561b,c886a540,3,c8f13240,...) at
VBoxDrvFreeBSDIOCtl+0x1ea
devfs_ioctl_f(c9171bd0,c028561b,c886a540,c89be400,c8f13240,...) at
devfs_ioctl_f+0xe9
kern_ioctl(c8f13240,16,c028561b,c886a540,40000000,...) at kern_ioctl+0x1cf
ioctl(c8f13240,ea94fcf8,c,c07c87ba,c0826e48,...) at ioctl+0x123
syscall(ea94fd38) at syscall+0x282
Xint0x80_syscall() at Xint0x80_syscall+0x20
--- syscall (54, FreeBSD ELF32, ioctl), eip = 0x28285d23, esp = 0xbf4b3d8c,
ebp = 0xbf4b3da8 ---
panic: blockable sleep lock (sleep mutex) 32 _at_ /usr/src/sys/vm/uma_core.c:1990
cpuid = 1
KDB: stack backtrace:
db_trace_self_wrapper(c07c4189,ea94f97c,c05bcab3,c07e6681,1,...) at
db_trace_self_wrapper+0x26
kdb_backtrace(c07e6681,1,c07c6f08,ea94f988,1,...) at kdb_backtrace+0x29
panic(c07c6f08,c07ddda6,c07a22da,c07dcb34,7c6,...) at panic+0x114
witness_checkorder(c1ce8788,9,c07dcb34,7c6,0,...) at witness_checkorder+0xaa
_mtx_lock_flags(c1ce8788,0,c07dcb34,7c6,c14c8284,...) at _mtx_lock_flags+0xb8
uma_zalloc_arg(c1ce0700,0,1,0,c,...) at uma_zalloc_arg+0xd0
malloc(1c,c14ca9d0,1,c9edd5d0,c14cab20,...) at malloc+0x108
rtMemAlloc(c,0,ea94facc,c14b0e62,c,...) at rtMemAlloc+0x36
RTMemAlloc(c,ea94fabc,0,0,c95b2a10,...) at RTMemAlloc+0x19
SUPR0ObjAddRefEx(c9edd5d0,c7e8f810,0,ea94fb04,c14b8e2b,...) at
SUPR0ObjAddRefEx+0x142
SUPR0ObjAddRef(c9edd5d0,c7e8f810,4,c7e8f810,0,...) at SUPR0ObjAddRef+0x20
RTHandleTableLookupWithCtx(c95b2a10,9,4,c886a540,c7e8f810,...) at
RTHandleTableLookupWithCtx+0xcb
SUPSemEventSignal(c7e8f810,9,c07b92b7,3,c8f13240,...) at
SUPSemEventSignal+0x56
supdrvIOCtl(c028561b,c14cab20,c7e8f810,c886a540,ea94fbd4,...) at
supdrvIOCtl+0x1ce7
VBoxDrvFreeBSDIOCtl(c95b6000,c028561b,c886a540,3,c8f13240,...) at
VBoxDrvFreeBSDIOCtl+0x1ea
devfs_ioctl_f(c9171bd0,c028561b,c886a540,c89be400,c8f13240,...) at
devfs_ioctl_f+0xe9
kern_ioctl(c8f13240,16,c028561b,c886a540,40000000,...) at kern_ioctl+0x1cf
ioctl(c8f13240,ea94fcf8,c,c07c87ba,c0826e48,...) at ioctl+0x123
syscall(ea94fd38) at syscall+0x282
Xint0x80_syscall() at Xint0x80_syscall+0x20
--- syscall (54, FreeBSD ELF32, ioctl), eip = 0x28285d23, esp = 0xbf4b3d8c,
ebp = 0xbf4b3da8 ---
Uptime: 4h21m34s
Physical memory: 2026 MB
Dumping 208 MB: 193 177 161 145 129 113 97 81 65 49 33 17

Reading symbols from /boot/modules/nvidia.ko...done.
Loaded symbols for /boot/modules/nvidia.ko
Reading symbols from /boot/kernel/ng_ubt.ko...Reading symbols from
/boot/kernel/ng_ubt.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/ng_ubt.ko
Reading symbols from /boot/kernel/netgraph.ko...Reading symbols from
/boot/kernel/netgraph.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/netgraph.ko
Reading symbols from /boot/kernel/ng_hci.ko...Reading symbols from
/boot/kernel/ng_hci.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/ng_hci.ko
Reading symbols from /boot/kernel/ng_bluetooth.ko...Reading symbols from
/boot/kernel/ng_bluetooth.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/ng_bluetooth.ko
Reading symbols from /boot/modules/vboxdrv.ko...done.
Loaded symbols for /boot/modules/vboxdrv.ko
Reading symbols from /boot/kernel/acpi.ko...Reading symbols from
/boot/kernel/acpi.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/acpi.ko
Reading symbols from /boot/kernel/ng_btsocket.ko...Reading symbols from
/boot/kernel/ng_btsocket.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/ng_btsocket.ko
#0  doadump () at pcpu.h:246
246     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) bt
#0  doadump () at pcpu.h:246
#1  0xc05bc809 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:419
#2  0xc05bcaef in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:575
#3  0xc05fab2b in witness_checkorder (lock=0xc1ce8788, flags=9,
file=0xc07dcb34 "/usr/src/sys/vm/uma_core.c", line=1990, interlock=0x0) at
/usr/src/sys/kern/subr_witness.c:1063
#4  0xc05aee67 in _mtx_lock_flags (m=0xc1ce8788, opts=0, file=0xc07dcb34
"/usr/src/sys/vm/uma_core.c", line=1990) at /usr/src/sys/kern/kern_mutex.c:200
#5  0xc06ecfea in uma_zalloc_arg (zone=0xc1ce0700, udata=0x0, flags=1) at
/usr/src/sys/vm/uma_core.c:1990
#6  0xc05ab878 in malloc (size=28, mtp=0xc14ca9d0, flags=1) at uma.h:305
#7  0xc14bf4b6 in rtMemAlloc () from /boot/modules/vboxdrv.ko
#8  0xc14bd519 in RTMemAlloc () from /boot/modules/vboxdrv.ko
#9  0xc14b0e62 in SUPR0ObjAddRefEx () from /boot/modules/vboxdrv.ko
#10 0xc14b0f00 in SUPR0ObjAddRef () from /boot/modules/vboxdrv.ko
#11 0xc14b8e2b in RTHandleTableLookupWithCtx () from /boot/modules/vboxdrv.ko
#12 0xc14b0c46 in SUPSemEventSignal () from /boot/modules/vboxdrv.ko
#13 0xc14b3dd7 in supdrvIOCtl () from /boot/modules/vboxdrv.ko
#14 0xc14aee3a in VBoxDrvFreeBSDIOCtl () from /boot/modules/vboxdrv.ko
#15 0xc0545faa in devfs_ioctl_f (fp=0xc886a540, com=3353933840,
data=0xc886a540, cred=0xc89be400, td=0xc8f13240) at
/usr/src/sys/fs/devfs/devfs_vnops.c:658
#16 0xc05fd53f in kern_ioctl (td=0xc8f13240, fd=22, com=3223868955,
data=0xc886a540 "birddrib(") at file.h:262
#17 0xc05fd6a9 in ioctl (td=0xc8f13240, uap=0xea94fcf8) at
/usr/src/sys/kern/sys_generic.c:677
#18 0xc074abc1 in syscall (frame=0xea94fd38) at
/usr/src/sys/i386/i386/trap.c:1073
#19 0xc0730390 in Xint0x80_syscall () at
/usr/src/sys/i386/i386/exception.s:261
#20 0x00000033 in ?? ()
Previous frame inner to this frame (corrupt stack?)

cheers.