Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address	= 0x9c
fault code		= supervisor read data  , page not present
instruction pointer	= 0x20:0xffffffff812da61b
stack pointer	        = 0x28:0xfffffe0016ad94f0
frame pointer	        = 0x28:0xfffffe0016ad9650
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		= 12 (swi4: clock (0))
trap number		= 12
panic: page fault
cpuid = 0
time = 2147483652
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe0016ad9150
vpanic() at vpanic+0x1e0/frame 0xfffffe0016ad91b0
panic() at panic+0x43/frame 0xfffffe0016ad9210
trap_fatal() at trap_fatal+0x4c6/frame 0xfffffe0016ad9290
trap_pfault() at trap_pfault+0x9f/frame 0xfffffe0016ad9300
trap() at trap+0x44d/frame 0xfffffe0016ad9420
calltrap() at calltrap+0x8/frame 0xfffffe0016ad9420
--- trap 0xc, rip = 0xffffffff812da61b, rsp = 0xfffffe0016ad94f0, rbp = 0xfffffe0016ad9650 ---
ip_output() at ip_output+0xe8b/frame 0xfffffe0016ad9650
igmp_intr() at igmp_intr+0x465/frame 0xfffffe0016ad9750
netisr_dispatch_src() at netisr_dispatch_src+0xe9/frame 0xfffffe0016ad97c0
igmp_fasttimo() at igmp_fasttimo+0x1082/frame 0xfffffe0016ad98a0
pffasttimo() at pffasttimo+0x6a/frame 0xfffffe0016ad98e0
softclock_call_cc() at softclock_call_cc+0x1dd/frame 0xfffffe0016ad99b0
softclock() at softclock+0xa3/frame 0xfffffe0016ad99f0
ithread_loop() at ithread_loop+0x2f2/frame 0xfffffe0016ad9a60
fork_exit() at fork_exit+0xb0/frame 0xfffffe0016ad9ab0
fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe0016ad9ab0
--- trap 0, rip = 0, rsp = 0, rbp = 0 ---
KDB: enter: panic
[ thread pid 12 tid 100018 ]
Stopped at      kdb_enter+0x6a: movq    $0,kdb_why