kern/53939: system panics on bringing vioif(4) interface up

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>Number:         53939
>Category:       kern
>Synopsis:       system panics on bringing vioif(4) interface up
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Feb 03 17:45:00 +0000 2019
>Originator:     Sevan Janiyan
>Release:        8.99.30 & 8.99.33
>Organization:
>Environment:
amd64
>Description:
VM is a bhyve guest, upon boot the system panics with the following back trace
 
Waiting for DAD to complete for statically configured addresses...
[   4.3541290] uvm_fault(0xffff80253f2272e0, 0x0, 1) -> e
[   4.3541290] fatal page fault in supervisor mode
[   4.3541290] trap type 6 code 0 rip 0xffffffff80de624d cs 0x8 rflags 0x10286 cr2 0x18 ilevel 0x6 rsp 0xffff850032b209a0
[   4.3541290] curlwp 0xffff80255391b1a0 pid 113.1 lowest kstack 0xffff850032b1d2c0
[   4.3541290] panic: trap
[   4.3541290] cpu0: Begin traceback...
[   4.3634952] vpanic() at netbsd:vpanic+0x16f
[   4.3634952] snprintf() at netbsd:snprintf
[   4.3634952] startlwp() at netbsd:startlwp
[   4.3634952] alltraps() at netbsd:alltraps+0xc8
[   4.3634952] vioif_init() at netbsd:vioif_init+0x99
[   4.3634952] ether_ioctl() at netbsd:ether_ioctl+0x131
[   4.3634952] vioif_ioctl() at netbsd:vioif_ioctl+0x2f
[   4.3735020] in_ifinit() at netbsd:in_ifinit+0x137
[   4.3735020] in_control() at netbsd:in_control+0x13e6
[   4.3735020] udp_ioctl_wrapper() at netbsd:udp_ioctl_wrapper+0x32
[   4.3735020] compat_ifioctl() at netbsd:compat_ifioctl+0x12f
[   4.3735020] doifioctl() at netbsd:doifioctl+0xeac
[   4.3735020] sys_ioctl() at netbsd:sys_ioctl+0x11c
[   4.3835103] syscall() at netbsd:syscall+0x173
[   4.3835103] --- syscall (number 54) ---
[   4.3835103] 734e72b1a88a:
[   4.3835103] cpu0: End traceback...

>How-To-Repeat:

>Fix: