Panic with umass device with EHCI enabled

HI,

I'm running a  FreeBSD 6.0-CURRENT with a kernel and world build on 22
march 2005,
# uname -a
FreeBSD venus 6.0-CURRENT FreeBSD 6.0-CURRENT #4: Tue Mar 22 18:11:22
CET 2005     dom_at_venus:/usr/obj/usr/src/sys/VENUS  i386

When I unplug my usb key on usb2 controller, I have a panic kernel.
====
umass0: at uhub3 port 2 (addr 2) disconnected
(da0:umass-sim0:0:0:0): lost device

Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0xdeadc116
fault code              = supervisor write, page not present
instruction pointer     = 0x8:0xc043982f
stack pointer           = 0x10:0xcc9d2cdc
frame pointer           = 0x10:0xcc9d2cf4
code segment            = base 0x0, limit 0xfffff, type 0x1b
                       = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 31 (swi2: cambio)
[thread pid 31 tid 100023 ]
Stopped at      camisr+0x12b:   decl    0x38(%eax)
db> trace
Tracing pid 31 tid 100023 td 0xc150d730
camisr(c06c4574) at camisr+0x12b
ithread_loop(c14e0c00,cc9d2d48,c14e0c00,c04d8ae4,0) at ithread_loop+0x120
fork_exit(c04d8ae4,c14e0c00,cc9d2d48) at fork_exit+0xa4
fork_trampoline() at fork_trampoline+0x8
--- trap 0x1, eip = 0, esp = 0xcc9d2d7c, ebp = 0 ---
db>
===

The dmesg and kernel config is attached.
Any help will be greatly appreciated. (please say me if you need more
information with step by step please, I'm not a developper :)

Regards
-- 
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a man to fish, feed him for life."