After suspend resume network manager fails to set default route entry to routing table for mobile broadband connection

[Pauli]

This is regression from 10.04.

It seems to reproduce often but not always which might point to some kind of race condition handled badly.

Basic setup:
* Huawei USB 3G modem
* Network manager set to auto connect with saved pin
* Laptop which has very few suspend-resume issues so I use suspending all the time

I noticed the bug that modem led and network manager indicated that there was a connection. But connection didn't seems to work.

My initial workaround in hurry was just to pull the modem from laptop and restart both modem manager and network manager. (they don't like modem unplugging or individual restarts but those are long standing separated bugs that I haven't cared to report) After restarting connection comes up working.

I decided to investigate what is broken after resume and I could narrow issue to be that default route is missing from routing table. That resulted to very simple fix where I can simple manually add the missing default route.

Broken table after suspend:

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
link-local * 255.255.0.0 U 1000 0 0 ppp0
rantapallo * 255.255.255.255 UH 750 0 0 ppp0

Working table before suspend:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default * 0.0.0.0 U 750 0 0 ppp0
link-local * 255.255.0.0 U 1000 0 0 ppp0
rantapallo * 255.255.255.255 UH 750 0 0 ppp0

Command to add the missing route manually:

sudo route add default netmask 0.0.0.0 metric 750 dev ppp0

That is at least so far only missing part of connection setup after suspend. I will report a separate bug if I see a different error causing similar reconnecting failure after suspend-resume.

apport should include syslog with detailed log from suspend-resume and service restarts to get correct route tables.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: network-manager 1.0.4-0ubuntu5
ProcVersionSignature: Ubuntu 4.2.0-15.18-generic 4.2.3
Uname: Linux 4.2.0-15-generic x86_64
ApportVersion: 2.19.1-0ubuntu2
Architecture: amd64
CurrentDesktop: GNOME
Date: Sat Oct 17 03:19:00 2015
InstallationDate: Installed on 2011-11-02 (1444 days ago)
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111011)
IpRoute:
 default dev ppp0 scope link metric 750
 169.254.0.0/16 dev ppp0 scope link metric 1000
 176.93.96.110 dev ppp0 proto kernel scope link src 176.93.96.110 metric 750
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
 WimaxEnabled=true
SourcePackage: network-manager
UpgradeStatus: Upgraded to wily on 2015-10-10 (6 days ago)
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH
 ttyUSB0 gsm connected /org/freedesktop/NetworkManager/Devices/3 Dna dna internet 17b039cf-5b74-42af-af9a-d84c2519b250 /org/freedesktop/NetworkManager/ActiveConnection/1
 eth0 ethernet unavailable /org/freedesktop/NetworkManager/Devices/0 -- -- --
 wlan0 wifi unavailable /org/freedesktop/NetworkManager/Devices/2 -- -- --
 lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/1 -- -- --
nmcli-nm: Error: command ['nmcli', '-f', 'all', 'nm'] failed with exit code 2: Error: Object 'nm' is unknown, try 'nmcli help'.

[Pauli (paniemin)]

Stupid me writing completely bogus. This modem wouldn't even work in 10.04. So obviously I tried to say regression was cause by upgraded from 15.05.

[Pauli (paniemin)]

Seems like network-manager 1.0.4-0ubuntu5.1 fixed this bug. That makes this like duplicate of LP: #1512749