Comment 11 for bug 1598312

The workaround makes networking very unstable (both WiFi and wired).

4.2.0-18 is OK.
4.2.0-19 is BROKEN.

No suspicious configuration changes:

$ diff /boot/config-4.2.0-18-generic /boot/config-4.2.0-19-generic
3c3
< # Linux/x86_64 4.2.0-18-generic Kernel Configuration
---
> # Linux/x86_64 4.2.0-19-generic Kernel Configuration
69c69
< CONFIG_VERSION_SIGNATURE="Ubuntu 4.2.0-18.22~14.04.1-generic 4.2.3"
---
> CONFIG_VERSION_SIGNATURE="Ubuntu 4.2.0-19.23~14.04.1-generic 4.2.6"
5334c5334,5335
< # CONFIG_SND_PCM_OSS is not set
---
> CONFIG_SND_PCM_OSS=m
> CONFIG_SND_PCM_OSS_PLUGINS=y
7530c7531,7532
< # CONFIG_AUFS_EXPORT is not set
---
> CONFIG_AUFS_EXPORT=y
> CONFIG_AUFS_INO_T_64=y

I'll get the ubuntu kernel source and try to bisect.