[Pkg-utopia-maintainers] Bug#1118279: network-manager: NM Bridge: Up command fails to activate port after GUI/Down failure

[Norbert]

Package: network-manager
Version: 1.52.1-1
Severity: normal
X-Debbugs-Cc: norbicki at gmx.com

A logical error occurs within the NetworkManager service when attempting to re-
activate a Bridge connection after it has been previously disconnected or
failed (e.g., via the KDE Plasma GUI applet).

In this state, running the primary activation command for the bridge fails to
bring up the connection fully. The root cause appears to be that the Bridge
Slave port is not automatically and reliably activated alongside the master
bridge connection, requiring manual intervention.

* What led up to the situation?

The system is configured with a Network Bridge and a corresponding Bridge Slave
(Port) connection, typically used for virtualisation (e.g., KVM/libvirt) on a
wired interface. The situation arose after attempting to disconnect and then
reconnect the bridge using the KDE Plasma Network Applet. This action resulted
in the bridge failing to fully transition to an active state.

* What exactly did you do (or not do) that was effective (or ineffective)?

Ineffective Actions:

    Clicking "Disconnect" then "Connect" within the KDE Plasma network applet.

    Running the command to activate the master bridge:
    Bash

    nmcli connection up bridge_profile_name

In both cases, the connection remained unusable, and VMs lost connectivity,
despite the NM status potentially showing an ambiguous state.

Effective Action (Workaround):

    Manually forcing the activation of the slave (port) connection:
    Bash

    nmcli connection up slave_port_profile_name

    Executing this single command immediately restored full functionality to
the entire Bridge connection.

* What was the outcome of this action?

The network bridge connection was fully and correctly restored after the manual
activation of the slave port. The bridge then functioned as expected.

* What outcome did you expect instead?

I expected the NetworkManager to reliably handle the entire activation process
when the master connection (the Bridge) is brought up.

Specifically, the command nmcli connection up bridge_profile_name (or using the
GUI) should be sufficient to properly reset and activate both the master bridge
interface and all its configured slave ports, without requiring any manual
activation of the slave port itself.


-- System Information:
Debian Release: 13.1
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 6.12.48+deb13-amd64 (SMP w/12 CPU threads; PREEMPT)
Locale: LANG=pl_PL.UTF-8, LC_CTYPE=pl_PL.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages network-manager depends on:
ii  adduser                         3.152
ii  dbus [default-dbus-system-bus]  1.16.2-2
ii  libaudit1                       1:4.0.2-2+b2
ii  libbluetooth3                   5.82-1.1
ii  libc6                           2.41-12
ii  libcurl3t64-gnutls              8.14.1-2
ii  libglib2.0-0t64                 2.84.4-3~deb13u1
ii  libgnutls30t64                  3.8.9-3
ii  libjansson4                     2.14-2+b3
ii  libmm-glib0                     1.24.0-1+deb13u1
ii  libndp0                         1.9-1+b1
ii  libnewt0.52                     0.52.25-1
ii  libnm0                          1.52.1-1
ii  libpsl5t64                      0.21.2-1.1+b1
ii  libreadline8t64                 8.2-6
ii  libselinux1                     3.8.1-1
ii  libsystemd0                     257.8-1~deb13u2
ii  libteamdctl0                    1.31-1+b2
ii  libudev1                        257.8-1~deb13u2

Versions of packages network-manager recommends:
ii  dnsmasq-base [dnsmasq-base]  2.91-1
ii  libpam-systemd               257.8-1~deb13u2
ii  modemmanager                 1.24.0-1+deb13u1
ii  network-manager-l10n         1.52.1-1
ii  polkitd                      126-2
ii  ppp                          2.5.2-1+1
ii  udev                         257.8-1~deb13u2
ii  wireless-regdb               2025.07.10-1
ii  wpasupplicant                2:2.10-24

Versions of packages network-manager suggests:
ii  iptables       1.8.11-2
pn  libteam-utils  <none>

Versions of packages network-manager is related to:
pn  isc-dhcp-client  <none>

-- no debconf information