[Pkg-utopia-maintainers] Bug#993051: avahi-daemon CPU usage increases over time

[Ryan Armstrong]

Package: avahi-daemon
Version: 0.8-5
Severity: normal

Dear Maintainer,

After upgrading to Debian Bullseye, I noticed that the Avahi CPU usage on my server machine was
quite high (eventually 100% of one core). After resetting Avahi, the CPU usage was normal then
eventually increased over time again until it was again rather high. The
increase appears to be (very roughly) 1 or 2% per hour on my rather humble Intel(R) Celeron(R)
CPU 4205U @ 1.80GHz.

Checking the journal, I only see the following sorts of lines:

Aug 25 16:21:30 zeta avahi-daemon[313333]: avahi_normalize_name() failed.
Aug 25 16:21:30 zeta avahi-daemon[313333]: avahi_key_new() failed.
Aug 25 16:21:30 zeta avahi-daemon[313333]: avahi_normalize_name() failed.
Aug 25 16:21:30 zeta avahi-daemon[313333]: avahi_key_new() failed.
Aug 25 16:21:31 zeta avahi-daemon[313333]: avahi_normalize_name() failed.
Aug 25 16:21:31 zeta avahi-daemon[313333]: avahi_key_new() failed.

Which was around the time I turned on another machine on my network.
However, the timing was not aligned with when Avahi CPU usage increased.
Instead, it seems to be aligned with when I turn on my printer, but nothing
of note was printed in the log when that happened.

Is there any means for me to gather additional information to help
diagnose this problem?

Thanks,
Ryan

-- System Information:
Debian Release: 11.0
   APT prefers stable-security
   APT policy: (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.10.0-8-amd64 (SMP w/2 CPU threads)
Locale: LANG=en_CA.UTF-8, LC_CTYPE=en_CA.UTF-8 (charmap=UTF-8), LANGUAGE=en_CA:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages avahi-daemon depends on:
ii  adduser              3.118
ii  bind9-host [host]    1:9.16.15-1
ii  dbus                 1.12.20-2
ii  init-system-helpers  1.60
ii  libavahi-common3     0.8-5
ii  libavahi-core7       0.8-5
ii  libc6                2.31-13
ii  libcap2              1:2.44-1
ii  libdaemon0           0.14-7.1
ii  libdbus-1-3          1.12.20-2
ii  libexpat1            2.2.10-2
ii  lsb-base             11.1.0

Versions of packages avahi-daemon recommends:
ii  libnss-mdns  0.14.1-2

Versions of packages avahi-daemon suggests:
pn  avahi-autoipd  <none>

-- no debconf information