/usr/sbin/NetworkManager:6:g_assertion_message:g_assertion_message_expr:nm_device_queue_activation:_internal_activate_device:_internal_activate_generic

[errors.ubuntu.com bug bridge]

The Ubuntu Error Tracker has been receiving reports about a problem regarding network-manager. This problem was most recently seen with package version 1.4.4-1ubuntu3, the problem page at https://errors.ubuntu.com/problem/b8e0244b05afe9f376ca190cbb5d6bbd0735de92 contains more details, including versions of packages affected, stacktrace or traceback, and individual crash reports.
If you do not have access to the Ubuntu Error Tracker you can request it at http://forms.canonical.com/reports/.