Fatal trap 12: page fault while in kernel mode
fault virtual address	= 0x0
fault code		= supervisor read, page not present
instruction pointer	= 0x8:0xc04fe96f
stack pointer		= 0x10:0xc9414ab0
frame pointer		= 0x10:0xc9414ad4
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		= 252 (natd)
kernel: type 12 trap, code=0
Stopped at m_free+0x4f:	cmpl	$0,0(%eax)
db> trace
m_free(c9414b98,c063ee1e,0,c1befb08,c9414b14) at m_free+0x4f
ip_input(c9414b98,c3,c06a5860,c9414cbc,246) at ip_input+0xc4
div_ouput(c1d04a50,c0fb1f00,c1befb00,0,c9414c20) at div_ouput+0x1ef
div_send(c1d04a50,0,c0fb1f00,c1befb00,0) at div_send+0x5b
sosend(c1d04a50,c1befb00,c9414c4c,c0fb1f00,0) at sosend+0x41d
kern_sendit(c1c8c640,3,c9414cc4,0,0) kern_sendit+0xf2
sendit(c1c8c640,3,c9414cc4,0,bfbeeddc) at sendit+0x16e
sendto(c1c8c640,c9414d14,c064ce16,3ee,6) at sendto+0x5b
syscall(2f,2f,2f,bfbeed80,1) at syscall+0x266
Xint0x80_syscall() at Xint0x80_syscall+0x1d
--- syscall (133, FreeBSD ELF32, sendto), eip = 0x180d092f, esp = 0xbfbeecec, ebp = 0xbfbfed98 ---