bin/55973: ntpd(8) does not notice all interface changes any more

[martin%NetBSD.org@localhost]

>Number:         55973
>Category:       bin
>Synopsis:       ntpd(8) does not notice all interface changes any more
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Feb 04 09:55:00 +0000 2021
>Originator:     Martin Husemann
>Release:        NetBSD 9.99.79
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD out-of-the-silent-planet.aprisoft.de 9.99.79 NetBSD 9.99.79 (GENERIC64) #187: Wed Feb 3 21:38:13 CET 2021 martin%seven-days-to-the-wolves.aprisoft.de@localhost:/work/src/sys/arch/evbarm/compile/GENERIC64 evbarm
Architecture: aarch64
Machine: evbarm
>Description:

This board has no RTC clock so usualy picks up / file system time at boot.
Due to other (unrelated) bugs it also has no network connectivity early at
boot. This means dhcpcd does not configure network before ntpd(8) starts,
but shortly after that netwok becomes available.

Nevertheless does ntpd stay in .INIT. state forever (actually only tested
for a few minutes):

 > ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 emmas.aprisoft. .INIT.          16 u    -   64    0    0.000   +0.000   0.000


When I restart ntpd manually, it ~immediately establishes contact:

 > ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 emmas.aprisoft. 44.66.217.167    3 u    2   64    1    0.114  +17976.   0.000


This used to work automatically w/o any manual intervention.

>How-To-Repeat:
s/a

>Fix:
n/a