Bug#1032561: iproute2: "tc filter show" always results in empty response

[Simon <simon@sarthur.dev>]

Package: iproute2
Version: 6.1.0-2
Severity: normal
X-Debbugs-Cc: simon@sarthur.dev

Dear Maintainer,

While testing CAKE traffic shaping, I could not see records or statistics for applied tc filters.
Filters do seem to be present and having an effect, but "tc filter show" always returns no output.

root@debian12:~# tc filter add dev eth2 parent ffff: matchall action mirred egress redirect dev ifb4eth2
root@debian12:~# tc filter
root@debian12:~# tc filter show
root@debian12:~# 

Tested on fresh Bookworm install and several other machines running various 6.1 based kernels with same result.

-- System Information:
Debian Release: bookworm/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 6.1.0-5-amd64 (SMP w/1 CPU thread; PREEMPT)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages iproute2 depends on:
ii  debconf [debconf-2.0]  1.5.82
ii  libbpf1                1:1.1.0-1
ii  libbsd0                0.11.7-2
ii  libc6                  2.36-8
ii  libcap2                1:2.66-3
ii  libcap2-bin            1:2.66-3
ii  libdb5.3               5.3.28+dfsg2-1
ii  libelf1                0.188-2.1
ii  libmnl0                1.0.4-3
ii  libselinux1            3.4-1+b5
ii  libtirpc3              1.3.3+ds-1
ii  libxtables12           1.8.9-2

Versions of packages iproute2 recommends:
pn  libatm1  <none>

Versions of packages iproute2 suggests:
pn  iproute2-doc  <none>
ii  python3       3.11.2-1

-- debconf information:
  iproute2/setcaps: false