Comment 23 for bug 1124803

NetworkManager 0.9.8.0 from Raring is not a solution.
It use /var/lib/NetworkManager/ directory to store .lease
files. It is not allowed by apparmor policy
isc-dhcp-client: /etc/apparmor/init/network-interface-security/sbin.dhclient

If permissions for /var/lib/NetworkManager is granted to dhclient,
dhclient is not stopped after 'stop network-manager'.
This leads to problems during shutdown.
Since network-manager-0.9.8.0 does not clean
/run/sendsigs.omit.d, dhclient is ignored by /etc/init.d/sendsigs.
When /etc/init.d/umountroot is running, dhclient is alive
and his lease file is open for writing.

The result is
mount: / is busy
and filesystem recovery during next boot.

If the patch, that fixes signal handling thread,
is applied to network-manager-0.9.6.0 then
dhcleint is stopped with network-manager
and root filesystem can be remounted readonly.