Problem with acd on upgrade to 1.52

[Beniamino Galvani]

On Thu, Jul 10, 2025 at 12:55:23PM +0200, Christian Schaubschläger wrote:
> Hi,
> 
> thanks for the quick response earlier. I think my reply with the full log attached got blocked... 
> so here's another try:
> 
> http://datenaustausch.s3.eu-west-1.amazonaws.com/Logs/daemon-list.log
> 
> Meanwhile I found out, that the error message below is also there when I use NM-1.48... so the problem might be unrelated to that particular error message...
> But maybe you can find a hint in the logfile.
> 
> And another thing: I get the same problem when i configure NM to use dhcpcd instead of the internal dhcp client.
> 
> And I also checked the NOARP flag: it's not set on the network interface. Interestingly, when I set it via a script in /etc/NetworkManger/dispatcher.d/, then the network setup succeeds! Only DNS does not work when NOARP is set... 

Hi,

I see two problems in the log.

First, the creation of the ACD probe fails. This shouldn't
happen. Perhaps are you building NM with eBPF support? If so, it's
possible that the process doesn't have the necessary capabilities to
use the eBPF program. Anyway, the logging needs to be improved to
indicate the exact cause for the failure.

Second, there is a mechanism that retries the ACD probe creation and
gives up after some seconds. Apparently this is not working and NM
never recovers, as the log shows:

Jul 10 09:08:23 acd[192.168.0.54, probing]: probing currently  stillnot possible (timeout 200 msec; failure to create nacd instance, retry probing on timeout)
Jul 10 09:08:25 acd[192.168.0.54, probing]: probing currently  stillnot possible (timeout 200 msec; failure to create nacd instance, retry probing on timeout)
Jul 10 09:08:29 acd[192.168.0.54, probing]: probing currently  stillnot possible (timeout 200 msec; failure to create nacd instance, retry probing on timeout)
...
Jul 10 09:08:34 acd[192.168.0.54, probing]: probing currently  stillnot possible (timeout 200 msec; failure to create nacd instance, retry probing on timeout)

I will investigate this and prepare a patch. In the meantime, you can
try disabling ACD for the connection:

 nmcli connection modify "Wired connection 1" ipv4.dad-timeout 0

Beniamino



> Thanks and best regards,
> Christian
> 
> 
> Am 10.07.25 um 10:02 schrieb Beniamino Galvani:
> > On Thu, Jul 10, 2025 at 09:31:58AM +0200, Christian Schaubschläger wrote:
> >> Hi list,
> >>
> >> I just upgraded from NetworkManager-1.48 to 1.52.1. Unfortunately this had the effect, that my wired interface, which is configured for using dhcp, does not get an IP address any more. From the networkmanager logs I can see that a dhcp request is sent and successfully answered, but then networkmanager gets stuck with this:
> >>
> >> Jul 10 09:08:34 lfs-sn NetworkManager[1043]: <trace> [1752138514.1285] l3cfg[751860e9573ab19e,ifindex=4]: acd[192.168.0.54, probing]: probing currently  stillnot possible (timeout 200 msec; failure to create nacd instance, retry probing on timeout)
> >> Jul 10 09:08:35 lfs-sn NetworkManager[1043]: <trace> [1752138515.6305] l3cfg[751860e9573ab19e,ifindex=4]: acd[192.168.0.54, probing]: probing currently  stillnot possible (timeout 200 msec; failure to create nacd instance, retry probing on timeout)
> >>
> >> Has anyone any clue what's wrong here?
> > Can you share the full activation log at trace level?
> >
> > Thanks,
> > Beniamino
> 
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