bin/55783: rndctl -L broken

[martin%NetBSD.org@localhost]

>Number:         55783
>Category:       bin
>Synopsis:       rndctl -L broken
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Nov 04 10:45:00 +0000 2020
>Originator:     Martin Husemann
>Release:        NetBSD 9.99.74
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD h-pulse.aprisoft.de 9.99.74 NetBSD 9.99.74 (GENERIC64) #160: Tue Oct 20 20:56:57 CEST 2020 martin%seven-days-to-the-wolves.aprisoft.de@localhost:/work/src/sys/arch/evbarm/compile/GENERIC64 evbarm
Architecture: aarch64
Machine: evbarm
>Description:

On a machine with no entropy:

 # sysctl kern.entropy
kern.entropy.collection = 1
kern.entropy.depletion = 0
kern.entropy.consolidate = -16384
kern.entropy.gather = -16384
kern.entropy.needed = 256
kern.entropy.pending = 0
kern.entropy.epoch = 20

I can not add entropy via rndctl -L:
 # rndctl -L /tmp/entropy
 # sysctl kern.entropy
kern.entropy.collection = 1
kern.entropy.depletion = 0
kern.entropy.consolidate = -16384
kern.entropy.gather = -16384
kern.entropy.needed = 256
kern.entropy.pending = 0
kern.entropy.epoch = 21

and there is no diagnostic message telling me what is wrong (epoch > 0 is
a hint, this machine used to have entropy and I manually depleted it for
testing).

>How-To-Repeat:
s/a

>Fix:
n/a