Comment 0 for bug 963106

During system shutdown, NetworkManager neither kills dhclient nor does it remove the dhclient pid file from the directory /var/run/sendsigs.omit.d. As a result, dhclient continues to hold the pid file open for write and when /etc/init.d/umountroot tries to remount the root filesystem read-only, the remount fails. The message:

mount: / is busy

is seen in the console, and the filesystem must be recovered at boot time:

[ 8.946427] EXT4-fs (sda1): INFO: recovery required on readonly filesystem
[ 8.947057] EXT4-fs (sda1): write access will be enabled during recovery
[ 11.234075] EXT4-fs (sda1): recovery complete

If shared libraries used by dhclient are updated before the reboot, orphaned inodes associated with the .so files are created. For example, doing "sudo apt-get install --reinstall libc6" and then rebooting leads to:

[ 8.356521] EXT4-fs (sda1): INFO: recovery required on readonly filesystem
[ 8.356521] EXT4-fs (sda1): write access will be enabled during recovery
[ 8.716544] EXT4-fs (sda1): orphan cleanup on readonly fs
[ 8.716544] EXT4-fs (sda1): ext4_orphan_cleanup: deleting unreferenced inode 313749
[ 8.724544] EXT4-fs (sda1): ext4_orphan_cleanup: deleting unreferenced inode 313733
[ 8.724544] EXT4-fs (sda1): ext4_orphan_cleanup: deleting unreferenced inode 313725
[ 8.724544] EXT4-fs (sda1): 3 orphan inodes deleted
[ 8.728544] EXT4-fs (sda1): recovery complete

This is network-manager 0.9.3.995+git201203152001.04b2a74-0ubuntu1 running under 12.04. I don't believe any actual data loss will occur as a result of this bug, but it's likely to produce much user anxiety. Also see Bug 952315, which misidentifies the cause of the problems as upstart.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: network-manager 0.9.3.995+git201203152001.04b2a74-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-20.32-generic 3.2.12
Uname: Linux 3.2.0-20-generic i686
ApportVersion: 1.95-0ubuntu1
Architecture: i386
CRDA: Error: command ['iw', 'reg', 'get'] failed with exit code 1: nl80211 not found.
Date: Fri Mar 23 07:42:20 2012
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111011)
IwConfig:
 lo no wireless extensions.

 eth0 no wireless extensions.
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
 WimaxEnabled=true
ProcEnviron:
 TERM=xterm
 LANG=en_US.UTF-8
 SHELL=/bin/bash
RfKill:

SourcePackage: network-manager
UpgradeStatus: Upgraded to precise on 2012-03-02 (20 days ago)