Eu tenho um Raspberry Pi executando o Raspbian e vejo esse erro ao inicializar ifplugd .
ifplugd(lo): Program execution failed, return value is 1.
De julgar a seção de log, parece terminar onde começou, com ifplugd initializing - talvez isso sugira que o processo teve sucesso no final.
Não tive problemas conhecidos com a minha Ethernet, por isso não tenho a certeza da importância deste erro.
Nov 27 12:36:39 raspberrypi ifplugd(lo)[203]: ifplugd 0.28 initializing.
Nov 27 12:36:39 raspberrypi ifplugd(lo)[203]: Using interface lo/00:00:00:00:00:00
Nov 27 12:36:39 raspberrypi ifplugd(lo)[203]: Using detection mode: SIOCETHTOOL
Nov 27 12:36:39 raspberrypi ifplugd(lo)[203]: Initialization complete, link beat detected.
Nov 27 12:36:39 raspberrypi ifplugd(lo)[203]: Executing '/etc/ifplugd/ifplugd.action lo up'.
Nov 27 12:36:39 raspberrypi systemd[1]: Found device /dev/ttyAMA0.
Nov 27 12:36:39 raspberrypi kernel: gpiomem-bcm2835 3f200000.gpiomem: Initialised: Registers at 0x3f200000
Nov 27 12:36:39 raspberrypi ifplugd(lo)[203]: client: /sbin/ifup: failed to open lockfile /run/network/.ifstate.lock: No such file or directory
Nov 27 12:36:39 raspberrypi ifplugd(lo)[203]: client: run-parts: /etc/ifplugd/action.d//ifupdown exited with return code 1
Nov 27 12:36:39 raspberrypi mtp-probe[215]: checking bus 1, device 6: "/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.5"
Nov 27 12:36:39 raspberrypi mtp-probe[215]: bus: 1, device: 6 was not an MTP device
Nov 27 12:36:39 raspberrypi mtp-probe[217]: checking bus 1, device 3: "/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.1"
Nov 27 12:36:39 raspberrypi mtp-probe[216]: checking bus 1, device 5: "/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.4"
Nov 27 12:36:39 raspberrypi mtp-probe[216]: bus: 1, device: 5 was not an MTP device
Nov 27 12:36:39 raspberrypi ifplugd(lo)[203]: Program execution failed, return value is 1.
Nov 27 12:36:39 raspberrypi mtp-probe[217]: bus: 1, device: 3 was not an MTP device
Nov 27 12:36:39 raspberrypi mtp-probe[227]: checking bus 1, device 4: "/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2"
Nov 27 12:36:39 raspberrypi systemd[1]: Found device /dev/mmcblk0p5.
Nov 27 12:36:39 raspberrypi systemd[1]: Starting File System Check on /dev/mmcblk0p5...
Nov 27 12:36:39 raspberrypi mtp-probe[227]: bus: 1, device: 4 was not an MTP device
Nov 27 12:36:39 raspberrypi ifplugd(eth0)[248]: ifplugd 0.28 initializing.
Pode não estar relacionado, mas vejo que está acessando mtp-probe nessa parte do log. Recentemente tive erros de log desse tipo:
Nov 26 21:50:51 raspberrypi systemd-udevd[184]: failed to execute '/lib/udev/mtp-probe' 'mtp-probe /sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.1 1 3': No such file or directory
que eu fui embora depois de apt-get install libmtp-runtime .