segfault shortly after connection to an USB modem is established

[Ali Reza Barkhordari]

I'm using my phone as an USB modem. It used to be working fine in 15.10, but now in 16.04 it disconnects within approximately 2 minutes when it connects.

Here's dmesg log **before** network manager fails:

[ 2493.046646] usb 1-1.1: new high-speed USB device number 6 using ehci-pci
[ 2493.139903] usb 1-1.1: New USB device found, idVendor=1004, idProduct=6344
[ 2493.139907] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 2493.139922] usb 1-1.1: Product: LGE Android Phone
[ 2493.139923] usb 1-1.1: Manufacturer: LG Electronics Inc.
[ 2493.139925] usb 1-1.1: SerialNumber: XXXXXXXXXXXX
[ 2493.230445] cdc_acm 1-1.1:1.2: ttyACM0: USB ACM device
[ 2493.230721] usbcore: registered new interface driver cdc_acm
[ 2493.230723] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
[ 2493.268457] usbcore: registered new interface driver cdc_ether
[ 2493.290079] rndis_host 1-1.1:1.0 usb0: register 'rndis_host' at usb-0000:00:1a.0-1.1, RNDIS device, 02:4d:41:43:34:07
[ 2493.290108] usbcore: registered new interface driver rndis_host
[ 2493.321367] rndis_host 1-1.1:1.0 enp0s26u1u1: renamed from usb0
[ 2493.343344] IPv6: ADDRCONF(NETDEV_UP): enp0s26u1u1: link is not ready

And dmesg log **after** network manager fails:

[ 2493.046646] usb 1-1.1: new high-speed USB device number 6 using ehci-pci
[ 2493.139903] usb 1-1.1: New USB device found, idVendor=1004, idProduct=6344
[ 2493.139907] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 2493.139922] usb 1-1.1: Product: LGE Android Phone
[ 2493.139923] usb 1-1.1: Manufacturer: LG Electronics Inc.
[ 2493.139925] usb 1-1.1: SerialNumber: LGD8552e4244b8
[ 2493.230445] cdc_acm 1-1.1:1.2: ttyACM0: USB ACM device
[ 2493.230721] usbcore: registered new interface driver cdc_acm
[ 2493.230723] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
[ 2493.268457] usbcore: registered new interface driver cdc_ether
[ 2493.290079] rndis_host 1-1.1:1.0 usb0: register 'rndis_host' at usb-0000:00:1a.0-1.1, RNDIS device, 02:4d:41:43:34:07
[ 2493.290108] usbcore: registered new interface driver rndis_host
[ 2493.321367] rndis_host 1-1.1:1.0 enp0s26u1u1: renamed from usb0
[ 2493.343344] IPv6: ADDRCONF(NETDEV_UP): enp0s26u1u1: link is not ready
[ 2527.615086] NetworkManager[1042]: segfault at 4e8 ip 000000000046c810 sp 00007ffdd47e0120 error 4 in NetworkManager[400000+2b9000]
[ 2529.423507] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 2529.425511] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 2529.728754] NetworkManager[4830]: segfault at 4e8 ip 000000000046c810 sp 00007ffc5a4cfda0 error 4 in NetworkManager[400000+2b9000]
[ 2530.383596] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 2530.394093] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 2530.634992] NetworkManager[4866]: segfault at 4e8 ip 000000000046c810 sp 00007fff61f7f060 error 4 in NetworkManager[400000+2b9000]
[ 2531.137181] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 2531.139427] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready

More info:

    Ubuntu 16.04.1 LTS
    network-manager 1.2.2-0ubuntu0.16.04.3

[Ali Reza Barkhordari (abforce)]

In Ubuntu 16.10, this bug still exists.