New and exciting panic, possibly re(4)

While screwing around with comcast, I can trivially get this panic out
of my desktop machine, and am very confused.  It seems to happen on link
change up/down events.  I'm running 11.0-CURRENT FreeBSD 11.0-CURRENT #5
r265280M.  I don't have any direct evidence that this is re(4), just a
hunch from some discussions in clusteradm_at_ 

This can happen when reconnecting my modem or simply issues a netif
restart.

Fatal trap 9: general protection fault while in kernel mode
cpuid = 5; apic id = 15
instruction pointer     = 0x20:0xffffffff80a4429e
stack pointer           = 0x28:0xfffffe046a7f5530
frame pointer           = 0x28:0xfffffe046a7f55d0
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         = 1306 (ifconfig)
trap number             = 9
panic: general protection fault
cpuid = 5
KDB: stack backtrace:
#0 0xffffffff80998510 at kdb_backtrace+0x60
#1 0xffffffff80959d05 at panic+0x155
#2 0xffffffff80d9f2ff at trap_fatal+0x38f
#3 0xffffffff80d9ef5d at trap+0x74d
#4 0xffffffff80d82282 at calltrap+0x8
#5 0xffffffff80aa0aa1 at in_ifadownkill+0xd1
#6 0xffffffff80a412f0 at rn_walktree+0x80
#7 0xffffffff80aa0942 at in_ifadown+0xc2
#8 0xffffffff80a95591 at in_difaddr_ioctl+0x3a1
#9 0xffffffff80a94763 at in_control+0x463
#10 0xffffffff80a3010c at ifioctl+0x145c
#11 0xffffffff809b1a5d at kern_ioctl+0x3cd
#12 0xffffffff809b163c at sys_ioctl+0x13c
#13 0xffffffff80d9fd1b at amd64_syscall+0x3fb
#14 0xffffffff80d8256b at Xfast_syscall+0xfb
Uptime: 10m12s
Reading symbols from /boot/kernel/zfs.ko.symbols...done.
Loaded symbols for /boot/kernel/zfs.ko.symbols
Reading symbols from /boot/kernel/opensolaris.ko.symbols...done.
Loaded symbols for /boot/kernel/opensolaris.ko.symbols
Reading symbols from /boot/modules/nvidia.ko...done.
Loaded symbols for /boot/modules/nvidia.ko
Reading symbols from /boot/kernel/linux.ko.symbols...done.
Loaded symbols for /boot/kernel/linux.ko.symbols
Reading symbols from /boot/modules/vboxdrv.ko...done.
Loaded symbols for /boot/modules/vboxdrv.ko
Reading symbols from /boot/kernel/linprocfs.ko.symbols...done.
Loaded symbols for /boot/kernel/linprocfs.ko.symbols
Reading symbols from /boot/kernel/fdescfs.ko.symbols...done.
Loaded symbols for /boot/kernel/fdescfs.ko.symbols
Reading symbols from /boot/modules/vboxguest.ko...done.
Loaded symbols for /boot/modules/vboxguest.ko
Reading symbols from /boot/modules/vboxvideo.ko...done.
Loaded symbols for /boot/modules/vboxvideo.ko
Reading symbols from /boot/kernel/drm.ko.symbols...done.
Loaded symbols for /boot/kernel/drm.ko.symbols
Reading symbols from /boot/kernel/ums.ko.symbols...done.
Loaded symbols for /boot/kernel/ums.ko.symbols
Reading symbols from /boot/kernel/uhid.ko.symbols...done.
Loaded symbols for /boot/kernel/uhid.ko.symbols
#0  doadump (textdump=<value optimized out>) at pcpu.h:219
219     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) #0  doadump (textdump=<value optimized out>) at pcpu.h:219
#1  0xffffffff80959888 in kern_reboot (howto=260)
    at /usr/src/sys/kern/kern_shutdown.c:449
#2  0xffffffff80959d44 in panic (fmt=<value optimized out>)
    at /usr/src/sys/kern/kern_shutdown.c:756
#3  0xffffffff80d9f2ff in trap_fatal (frame=<value optimized out>, 
    eva=<value optimized out>) at /usr/src/sys/amd64/amd64/trap.c:882
#4  0xffffffff80d9ef5d in trap (frame=<value optimized out>)
    at /usr/src/sys/amd64/amd64/trap.c:224
#5  0xffffffff80d82282 in calltrap ()
    at /usr/src/sys/amd64/amd64/exception.S:231
#6  0xffffffff80a4429e in rt_expunge (rnh=0x7f00000000000210, 
    rt=0xfffff800148e10c8) at /usr/src/sys/net/route.c:930
#7  0xffffffff80aa0aa1 in in_ifadownkill (rn=0xfffff800148e10c8, 
    xap=0xfffffe046a7f5660) at /usr/src/sys/netinet/in_rmx.c:414
#8  0xffffffff80a412f0 in rn_walktree (h=<value optimized out>, 
    f=0xffffffff80aa09d0 <in_ifadownkill>, w=0xfffffe046a7f5660)
    at /usr/src/sys/net/radix.c:1097
#9  0xffffffff80aa0942 in in_ifadown (ifa=0xfffff8000d542300, delete=1)
    at /usr/src/sys/netinet/in_rmx.c:447
#10 0xffffffff80a95591 in in_difaddr_ioctl (data=<value optimized out>, 
    ifp=0xfffff8000d249000, td=<value optimized out>)
    at /usr/src/sys/netinet/in.c:580
#11 0xffffffff80a94763 in in_control (so=<value optimized out>, 
    cmd=<value optimized out>, data=0xfffff80126c642c0 "lo0", 
    ifp=0xfffff8000d249000, td=0xfffff80108ad6000)
    at /usr/src/sys/netinet/in.c:219
#12 0xffffffff80a3010c in ifioctl (so=0xfffff80014839700,
cmd=2149607705, 
    data=0xfffff80126c642c0 "lo0", td=0xfffff80108ad6000)
    at /usr/src/sys/net/if.c:2638
#13 0xffffffff809b1a5d in kern_ioctl (td=0xfffff80108ad6000, 
    fd=<value optimized out>, com=0) at file.h:323
#14 0xffffffff809b163c in sys_ioctl (td=0xfffff80108ad6000, 
    uap=0xfffffe046a7f59c0) at /usr/src/sys/kern/sys_generic.c:702
#15 0xffffffff80d9fd1b in amd64_syscall (td=0xfffff80108ad6000,
traced=0)
    at subr_syscall.c:133
#16 0xffffffff80d8256b in Xfast_syscall ()
    at /usr/src/sys/amd64/amd64/exception.S:390
#17 0x0000000800fb26fa in ?? ()
Previous frame inner to this frame (corrupt stack?)
Current language:  auto; currently minimal
(kgdb)