NetworkManager fails to detect when an ethernet device gets unplugged

[Dima Ryazanov]

Whenever I unplug my USB ethernet adapter, NetworkManager stays in the "connected" state. There are a few errors in syslog; it also mentions a bug related to unmanaged devices, but the device is (or should be) managed by NetworkManager:

Dec 3 17:20:31 dima-xps kernel: [15360.449644] usb 3-1: USB disconnect, device number 2
Dec 3 17:20:31 dima-xps kernel: [15360.449655] usb 3-1.2: USB disconnect, device number 3
Dec 3 17:20:31 dima-xps kernel: [15360.449816] smsc75xx 3-1.2:1.0 eth0: unregister 'smsc75xx' usb-0000:03:00.0-1.2, smsc75xx USB 2.0 Gigabit Ethernet
Dec 3 17:20:31 dima-xps avahi-daemon[540]: Interface eth0.IPv4 no longer relevant for mDNS.
Dec 3 17:20:31 dima-xps avahi-daemon[540]: Leaving mDNS multicast group on interface eth0.IPv4 with address 172.16.10.140.
Dec 3 17:20:31 dima-xps dhclient: receive_packet failed on eth0: Network is down
Dec 3 17:20:31 dima-xps kernel: [15360.480394] usb 3-1.4: USB disconnect, device number 4
Dec 3 17:20:31 dima-xps NetworkManager[835]: <info> (eth0): carrier now OFF (device state 100, deferring action for 4 seconds)
Dec 3 17:20:31 dima-xps avahi-daemon[540]: Withdrawing address record for 2620:c6:8000:100:20e:c6ff:fe89:aab9 on eth0.
Dec 3 17:20:31 dima-xps avahi-daemon[540]: Withdrawing address record for 172.16.10.140 on eth0.
Dec 3 17:20:31 dima-xps avahi-daemon[540]: Withdrawing workstation service for eth0.
Dec 3 17:20:31 dima-xps NetworkManager[835]: SCPlugin-Ifupdown: devices removed (path: /sys/devices/pci0000:00/0000:00:1c.3/0000:03:00.0/usb3/3-1/3-1.2/3-1.2:1.0/net/eth0, iface: eth0)
Dec 3 17:20:31 dima-xps NetworkManager[835]: <info> (eth0): device state change: activated -> unmanaged (reason 'removed') [100 10 36]
Dec 3 17:20:31 dima-xps NetworkManager[835]: <info> (eth0): deactivating device (reason 'removed') [36]
Dec 3 17:20:31 dima-xps NetworkManager[835]: <info> (eth0): canceled DHCP transaction, DHCP client pid 1862
Dec 3 17:20:31 dima-xps NetworkManager[835]: <warn> sysctl: failed to open '/proc/sys/net/ipv6/conf/eth0/accept_ra': (2) No such file or directory
Dec 3 17:20:31 dima-xps NetworkManager[835]: <warn> sysctl: failed to open '/proc/sys/net/ipv6/conf/eth0/use_tempaddr': (2) No such file or directory
Dec 3 17:20:31 dima-xps NetworkManager[835]: <warn> (3) failed to find interface name for index
Dec 3 17:20:31 dima-xps NetworkManager[835]: nm_system_iface_flush_routes: assertion 'iface != NULL' failed
Dec 3 17:20:31 dima-xps NetworkManager[835]: <warn> (3) failed to find interface name for index
Dec 3 17:20:31 dima-xps NetworkManager[835]: <warn> DNS: plugin dnsmasq update failed
Dec 3 17:20:31 dima-xps NetworkManager[835]: <info> Removing DNS information from /sbin/resolvconf
Dec 3 17:20:31 dima-xps dnsmasq[1434]: setting upstream servers from DBus
Dec 3 17:20:31 dima-xps NetworkManager[835]: <info> (eth0): cleaning up...
Dec 3 17:20:31 dima-xps NetworkManager[835]: <warn> (3) failed to find interface name for index
Dec 3 17:20:31 dima-xps NetworkManager[835]: (nm-system.c:766):nm_system_iface_get_flags: runtime check failed: (iface != NULL)
Dec 3 17:20:31 dima-xps NetworkManager[835]: <error> [1386120031.651217] [nm-system.c:768] nm_system_iface_get_flags(): (unknown): failed to get interface link object
Dec 3 17:20:31 dima-xps NetworkManager[835]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: network-manager 0.9.8.0-0ubuntu22
ProcVersionSignature: Ubuntu 3.8.0-29.42-generic 3.8.13.5
Uname: Linux 3.8.0-29-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
Date: Tue Dec 3 17:23:20 2013
EcryptfsInUse: Yes
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
InstallationDate: Installed on 2013-04-05 (243 days ago)
InstallationMedia: Kubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.1)
IpRoute:
 default via 172.16.80.1 dev wlan0 proto static
 172.16.80.0/22 dev wlan0 proto kernel scope link src 172.16.80.167 metric 9
MarkForUpload: True
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
 WimaxEnabled=true
SourcePackage: network-manager
UpgradeStatus: Upgraded to saucy on 2013-10-24 (40 days ago)
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH
 wlan0 802-11-wireless connected /org/freedesktop/NetworkManager/Devices/0
nmcli-nm:
 RUNNING VERSION STATE NET-ENABLED WIFI-HARDWARE WIFI WWAN-HARDWARE WWAN
 running 0.9.8.0 connected enabled enabled enabled enabled disabled