Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address	= 0xffffffffffffffff
fault code		= supervisor write data, page not present
instruction pointer	= 0x20:0xffffffff81947ff0
stack pointer	        = 0x28:0xfffffe0057352500
frame pointer	        = 0x28:0xfffffe0057352530
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 (swi1: netisr 0)
rdi: fffffe0077da1a80 rsi: 0000000000000000 rdx: 00000000aa0114ac
rcx: 0000000000000000  r8: 0000000000000000  r9: 0000000000000001
rax: ffffffffffffffff rbx: fffffe0077da1ac4 rbp: fffffe0057352530
r10: aa0114acaa0114ac r11: 000000000000001f r12: ffffffffffffffff
r13: fffffe0077da1cd0 r14: fffffe0077da1a80 r15: fffffe0077da1a88
trap number		= 12
panic: page fault
cpuid = 0
time = 13
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0xc6/frame 0xfffffe0057351d30
kdb_backtrace() at kdb_backtrace+0xd0/frame 0xfffffe0057351e90
vpanic() at vpanic+0x257/frame 0xfffffe0057352050
panic() at panic+0xb5/frame 0xfffffe0057352110
trap_pfault() at trap_pfault+0xaec/frame 0xfffffe0057352250
trap() at trap+0x78e/frame 0xfffffe0057352430
calltrap() at calltrap+0x8/frame 0xfffffe0057352430
--- trap 0xc, rip = 0xffffffff81947ff0, rsp = 0xfffffe0057352500, rbp = 0xfffffe0057352530 ---
in_pcbremhash_locked() at in_pcbremhash_locked+0x110/frame 0xfffffe0057352530
in_pcbdrop() at in_pcbdrop+0x98/frame 0xfffffe0057352550
tcp_close() at tcp_close+0x177/frame 0xfffffe0057352610
tcp_do_segment() at tcp_do_segment+0x1469/frame 0xfffffe00573528f0
tcp_input_with_port() at tcp_input_with_port+0x21ba/frame 0xfffffe0057352bb0
tcp_input() at tcp_input+0x1f/frame 0xfffffe0057352bd0
ip_input() at ip_input+0xa95/frame 0xfffffe0057352cf0
swi_net() at swi_net+0x2b8/frame 0xfffffe0057352d90
ithread_loop() at ithread_loop+0x4ec/frame 0xfffffe0057352ef0
fork_exit() at fork_exit+0xcc/frame 0xfffffe0057352f30
fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe0057352f30
--- trap 0, rip = 0, rsp = 0, rbp = 0 ---
KDB: enter: panic
[ thread pid 12 tid 100033 ]
Stopped at      kdb_enter+0x6e: movq    $0,0x23e7bb7(%rip)
db> set $lines = 0
db> set $maxwidth = 0
db> show registers
cs                        0x20
ds                        0x3b
es                        0x3b
fs                        0x13
gs                        0x1b
ss                        0x28
rax                       0x12
rcx         0xfffffe00033eee30
rdx                          0
rbx         0xffffffff82752f40  .str.27
rsp         0xfffffe0057351e70
rbp         0xfffffe0057351e90
rsi                          0
rdi         0xffffffff815dbb59  printf+0x149
r8                           0
r9                  0xffffffff
r10                          0
r11                       0x17
r12         0xfffffe000801f740
r13         0xfffffffffffffffe
r14         0xffffffff82752f40  .str.27
r15                          0
rip         0xffffffff815c64de  kdb_enter+0x6e
rflags                    0x46
kdb_enter+0x6e: movq    $0,0x23e7bb7(%rip)
db> show proc
Process 12 (intr) at 0xfffffe0008006580:
 state: NORMAL
 uid: 0  gids: 0
 parent: pid 0 at 0xffffffff839387c0
 ABI: null
 flag: 0x10000284  flag2: 0
 reaper: 0xffffffff839387c0 reapsubtree: 12
 sigparent: 20
 vmspace: 0xffffffff83939760
   (map 0xffffffff83939760)
   (map.pmap 0xffffffff83939800)
   (pmap 0xffffffff83939870)
 threads: 20
100013                   I                                   [swi6: task queue]
100014                   I                                   [swi6: Giant taskq]
100016                   I                                   [swi5: fast taskq]
100033                   Run     CPU 0                       [swi1: netisr 0]
100034                   I                                   [swi1: hpts]
100035                   I                                   [swi1: hpts]
100048                   I                                   [irq24: virtio_pci0]
100049                   I                                   [irq25: virtio_pci0]
100050                   I                                   [irq26: virtio_pci0]
100051                   I                                   [irq27: virtio_pci0]
100052                   I                                   [irq28: virtio_pci1]
100053                   I                                   [irq29: virtio_pci1]
100054                   I                                   [irq30: virtio_pci1]
100055                   I                                   [irq31: virtio_pci1]
100056                   I                                   [irq32: virtio_pci1]
100061                   I                                   [irq10: virtio_pci2]
100063                   I                                   [irq1: atkbd0]
100064                   I                                   [irq12: psm0]
100065                   I                                   [swi0: uart uart++]
100069                   I                                   [swi1: pf send]
db>