panic in ttwakeup

Hi. Got this panic while fooling around with jails. Can't remember what I 
did unfortunately.

kgdb barfed at the frame at address 0 in the backtrace command so I 
couldn't extract any more useful data except for the following.

I guess this is related to kern/103520

kernel is from Mon Oct 23 10:42:06 CEST 2006

Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x0
fault code              = supervisor read, page not present
instruction pointer     = 0x20:0x0
stack pointer           = 0x28:0xd59f892c
frame pointer           = 0x28:0xd59f8940
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         = 31026 (script)
trap number             = 12
panic: page fault
KDB: stack backtrace:
kdb_backtrace(100,c2816bd0,28,d59f88ec,c,...) at kdb_backtrace+0x29
panic(c0642f3f,c06642d6,0,0,fffff,...) at panic+0xa8
trap_fatal(d59f88ec,0,c2816bd0,c280f71c,0,...) at trap_fatal+0x2b6
trap_pfault(d59f88ec,0,0) at trap_pfault+0x1cb
trap(d59f0008,c0540028,c22f0028,c28f5400,c28c9a80,...) at trap+0x38d
calltrap() at calltrap+0x5
--- trap 0xc, eip = 0, esp = 0xd59f892c, ebp = 0xd59f8940 ---
(null)(c219f888,0,0,c219f810,c219f800,...) at 0
ttwakeup(c219f800,c219f800,c219f800,c28c9a80,d59f8990,...) at ttwakeup+0x65
ttymodem(c219f800,1) at ttymodem+0x170
ptcopen(c28f5400,3,2000,c2816bd0) at ptcopen+0x8c
giant_open(c28f5400,3,2000,c2816bd0) at giant_open+0x4b
devfs_open(d59f8a20) at devfs_open+0x1cf
VOP_OPEN_APV(c067b540,d59f8a20) at VOP_OPEN_APV+0x38
vn_open_cred(d59f8b88,d59f8c88,0,c2b20200,4,...) at vn_open_cred+0x453
vn_open(d59f8b88,d59f8c88,0,4) at vn_open+0x1e
kern_open(c2816bd0,bfbfe2a0,0,3,0,...) at kern_open+0xb9
open(c2816bd0,d59f8d04) at open+0x18
syscall(3b,3b,3b,bfbfe2ab,ffffffff,...) at syscall+0x2ae
Xint0x80_syscall() at Xint0x80_syscall+0x1f
--- syscall (5, FreeBSD ELF32, open), eip = 0x28146e0f, esp = 0xbfbfe26c, ebp = 0xbfbfe2c8 ---

Cheers
Michiel