bin/52695: rndc-confgen takes forever

[martin%NetBSD.org@localhost]

>Number:         52695
>Category:       bin
>Synopsis:       rndc-confgen takes forever
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Nov 03 13:50:00 +0000 2017
>Originator:     Martin Husemann
>Release:        NetBSD 8.0_BETA
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD unpluged.duskware.de 8.0_BETA NetBSD 8.0_BETA (UNPLUGED) #13: Wed Oct 18 07:12:50 CEST 2017 martin%seven-days-to-the-wolves.aprisoft.de@localhost:/work/src-8/sys/arch/evbarm/compile/UNPLUGED evbarm
Architecture: earm
Machine: evbarm
>Description:

Generating a rndc.key for named at first startup takes ages (if not literally),
apparently blocking on select() trying to read random entropy.

If this happens at boot time it will usually happen before sshd comes
up, so you can't even log in and "do something" about it.

On this machine rndctl -l shows:

Source                 Bits Type      Flags
wd1                       8 disk estimate, collect, v, t, dt
wd0                       8 disk estimate, collect, v, t, dt
ucom7                     0 tty  estimate, collect, v, t, dt
ucom6                     0 tty  estimate, collect, v, t, dt
ucom5                     0 tty  estimate, collect, v, t, dt
ucom4                     0 tty  estimate, collect, v, t, dt
ucom3                     0 tty  estimate, collect, v, t, dt
ucom2                     0 tty  estimate, collect, v, t, dt
ucom1                     0 tty  estimate, collect, v, t, dt
ucom0                     0 tty  estimate, collect, v, t, dt
sd1                       0 disk estimate, collect, v, t, dt
sd0                       0 disk estimate, collect, v, t, dt
cpu0                   1389 vm   estimate, collect, v, t, dv
mvgbe1                    0 net  v, t, dt
mvgbe0                    0 net  v, t, dt
system-power              0 power estimate, collect, v, t, dt
autoconf                  8 ???  estimate, collect, t, dt
printf                    0 ???  collect


>How-To-Repeat:

enable named in /etc/rc.conf

>Fix:
n/a