e4defrag segfaults, turns disk inacessible

[Janis Petersons]

While in the middle of defragmenting a mounted ext4 partition e4defrag segfaults. The message "Segfault" is printed into stdout. After failing e4defrag presumably locks write access to the disk or limits access speeds severely, as programs can still be executed but not always, although more time is needed for any task. For example opening a new bash terminal session and typing in one command may work. However, after that the terminal becomes unresponsive and only responds to a Ctr+D. This was tested for both terminal clients running in xserver and the tty. Problem does not persist after reboot. Reboots can't always be completed successfully, requiring a hard reset. Home and root exist on separate partitions on the same drive.
Steps to reproduce:
1. Perform a lengthy defragmentation. This was tested for /, /home and a separate folder on /home.
2. After some time segfault occurs.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: e2fsprogs 1.42-1ubuntu2
ProcVersionSignature: Ubuntu 3.2.0-39.62-generic 3.2.39
Uname: Linux 3.2.0-39-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.0.1-0ubuntu17.1
Architecture: amd64
Date: Tue Mar 19 17:29:33 2013
InstallationMedia: Kubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120820.1)
MarkForUpload: True
SourcePackage: e2fsprogs
UpgradeStatus: No upgrade log present (probably fresh install)