bin/57952: dhcpcd(8) inexplicably terminated in the night

[campbell+netbsd%mumble.net@localhost]

>Number:         57952
>Category:       bin
>Synopsis:       dhcpcd(8) inexplicably terminated in the night
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Feb 22 15:30:00 +0000 2024
>Originator:     Taylor R Campbell
>Release:        10.0_RC3
>Organization:
The NetBSDCD Foundation
>Environment:
NetBSD nanocons.local 10.0_RC3 NetBSD 10.0_RC3 (GENERIC64) #15: Wed Jan 17 05:31:14 UTC 2024  root@manticore.local:/usr/obj/10/evbarm64/sys/arch/evbarm/compile/GENERIC64 evbarm
>Description:
Some time during the night, dhcpcd terminated on two different hosts on my network without explaining why.  No core dump, no log messages obviously explaining what happened.  I may have been configuring a network device at the time, which I'll call ${ROGUE_DEVICE}, but I don't remember what stage in the misconfiguration I was in.  I may have wound up with two IPv6 routers and DHCPv6 servers at a time on the network.

Relevant log messages from the previous half hour or so, with IPv6 addresses replaced by symbolic labels:

<daemon.info>Feb 22 02:46:12 nanocons dhcpcd[622]: ure0: Router Advertisement from fe80::${ROGUEDEVICE}
<daemon.info>Feb 22 02:46:13 nanocons dhcpcd[622]: urtwn0: Router Advertisement from fe80::${ROGUEDEVICE}
<daemon.info>Feb 22 02:46:16 nanocons dhcpcd[622]: ure0: adding address ${GLOBALPREFIX}:${URE0_GLOBAL}/64
<daemon.info>Feb 22 02:46:16 nanocons dhcpcd[622]: ure0: adding address ${LOCALPREFIX}:${URE0_LOCAL}/64
<daemon.info>Feb 22 02:46:16 nanocons dhcpcd[622]: urtwn0: adding address ${GLOBALPREFIX}:${URTWN0_GLOBAL}/64
<daemon.info>Feb 22 02:46:16 nanocons dhcpcd[622]: urtwn0: adding address ${LOCALPREFIX}:${URTWN0_LOCAL}/64
<daemon.warn>Feb 22 02:51:42 nanocons dhcpcd[622]: ure0: fe80::${ROGUEDEVICE}: no longer a default router
<daemon.warn>Feb 22 02:51:43 nanocons dhcpcd[622]: urtwn0: fe80::${ROGUEDEVICE}: no longer a default router
<daemon.info>Feb 22 03:04:21 nanocons dhcpcd[622]: ure0: deleting address ${GLOBALPREFIX}:${URE0_GLOBAL}/64
<daemon.info>Feb 22 03:04:21 nanocons dhcpcd[622]: ure0: deleting address ${LOCALPREFIX}:${URE0_LOCAL}/64
<daemon.info>Feb 22 03:04:21 nanocons dhcpcd[622]: urtwn0: deleting address ${GLOBALPREFIX}:${URTWN0_GLOBAL}/64
<daemon.info>Feb 22 03:04:21 nanocons dhcpcd[622]: urtwn0: deleting address ${LOCALPREFIX}:${URTWN0_LOCAL}/64
<daemon.info>Feb 22 03:04:25 nanocons dhcpcd[622]: ure0: adding address ${LOCALPREFIX}:${URE0_LOCAL}/64
<daemon.info>Feb 22 03:04:25 nanocons dhcpcd[622]: ure0: adding address ${GLOBALPREFIX}:${URE0_GLOBAL}/64
<daemon.info>Feb 22 03:04:25 nanocons dhcpcd[622]: urtwn0: adding address ${LOCALPREFIX}:${URTWN0_LOCAL}/64
<daemon.info>Feb 22 03:04:25 nanocons dhcpcd[622]: urtwn0: adding address ${GLOBALPREFIX}:${URTWN0_GLOBAL}/64
<daemon.err>Feb 22 03:07:51 nanocons dhcpcd[622]: ps_sendcmdmsg: No buffer space available
<daemon.err>Feb 22 03:07:51 nanocons dhcpcd[622]: ps_inet_recvra: No buffer space available
<daemon.warn>Feb 22 03:07:59 nanocons dhcpcd[622]: ure0: fe80::${ROGUEDEVICE}: no longer a default router
<daemon.warn>Feb 22 03:08:02 nanocons syslogd[423]: last message repeated 5 times
<daemon.warn>Feb 22 03:08:02 nanocons dhcpcd[622]: urtwn0: fe80::${ROGUEDEVICE}: no longer a default router
<daemon.warn>Feb 22 03:08:02 nanocons dhcpcd[622]: ure0: fe80::${ROGUEDEVICE}: no longer a default router
<daemon.warn>Feb 22 03:08:02 nanocons dhcpcd[622]: ure0: fe80::${ROGUEDEVICE}: no longer a default router
<daemon.warn>Feb 22 03:08:03 nanocons dhcpcd[622]: urtwn0: fe80::${ROGUEDEVICE}: no longer a default router
<daemon.warn>Feb 22 03:08:03 nanocons dhcpcd[622]: ure0: fe80::${ROGUEDEVICE}: no longer a default router
<daemon.warn>Feb 22 03:08:06 nanocons syslogd[423]: last message repeated 6 times
<daemon.err>Feb 22 03:08:06 nanocons dhcpcd[622]: ps_inet_dodispatch: Connection reset by peer
<daemon.err>Feb 22 03:08:06 nanocons dhcpcd[622]: control_free: No such file or directory
<daemon.err>Feb 22 03:08:06 nanocons dhcpcd[622]: ps_sendpsmmsg: Destination address required
<daemon.err>Feb 22 03:08:06 nanocons dhcpcd[622]: ps_dostop: Destination address required

>How-To-Repeat:
not sure
>Fix:
Yes, please!

Ideally, mere network conditions should not provoke dhcpcd to terminate.

Preferably, dhcpcd would at least give a reason for each way that it does terminate.

At least it didn't take down the network configuration when it did so I was still able to ssh into the machines where it terminated.