a panic on uart_z8530_class?

Hello,

Anyone encountered this panic on recent CURRENT kernel?

[root_at_test ~]# uname -a
FreeBSD test 9.0-CURRENT FreeBSD 9.0-CURRENT #16: Sun May  2 00:24:12 PDT 2010     root_at_test:/usr/obj/usr/src/sys/GENERIC  amd64

[root_at_test /home/freebsd/sys/modules/bwn]# ifconfig wlan0 create wlandev bwn0

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address   = 0x0
fault code              = supervisor read instruction, page not present
instruction pointer     = 0x20:0x0
stack pointer           = 0x28:0xffffff8073cdd810
frame pointer           = 0x28:0xffffff8073cdd8e0
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         = 1795 (ifconfig)
[ thread pid 1795 tid 100096 ]
Stopped at      0:      *** error reading from address 0 ***
db> bt
Tracing pid 1795 tid 100096 td 0xffffff0003d8b390
uart_z8530_class() at 0
ifc_simple_create() at ifc_simple_create+0x89
if_clone_createif() at if_clone_createif+0x64
ifioctl() at ifioctl+0x685
kern_ioctl() at kern_ioctl+0xc5
ioctl() at ioctl+0xfd
syscall() at syscall+0x102
Xfast_syscall() at Xfast_syscall+0xe1
--- syscall (54, FreeBSD ELF64, ioctl), rip = 0x800b86d0c, rsp = 0x7fffffffe2e8, rbp = 0x7fffffffee36 ---
db> call doadump
Physical memory: 3916 MB
Dumping 1239 MB: 1224 1208 1192 1176 1160 1144 1128 1112 1096 1080 1064 1048 1032 1016 1000 984 968 952 936 920 904 888 872 856 840 824 808 792 776 760 744 728 712 696 680 664 648 632 616 600 584 568 552 536 520 504 488 472 456 440 424 408 392 376 360 344 328 312 296 280 264 248 232 216 200 184 168 152 136 120 104 88 72 56 40 24 8
Dump complete
= 0
db> reset

[root_at_test ~]# kgdb /boot/kernel/kernel /var/crash/vmcore.1
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This GDB was configured as "amd64-marcel-freebsd"...
Cannot access memory at address 0xffffff0127ffffe0
(kgdb) bt
#0  0x0000000000000000 in ?? ()
Cannot access memory at address 0x0
(kgdb) q

regards,
Weongyo Jeong