nfs-kernel-server init script leaves nfsd fs mounted

Binary package hint: nfs-kernel-server

Description: Ubuntu 8.04.1
Release: 8.04
nfs-kernel-server:
  Installed: 1:1.1.2-2ubuntu2.1
  Candidate: 1:1.1.2-2ubuntu2.1
  Version table:
 *** 1:1.1.2-2ubuntu2.1 0
        500 http://us.archive.ubuntu.com hardy-updates/main Packages
        100 /var/lib/dpkg/status
     1:1.1.2-2ubuntu2 0
        500 http://us.archive.ubuntu.com hardy/main Packages

When starting nfs-kernel-server, /proc/fs/nfsd is (correctly) mounted. When stopping nfs-kernel-server, however, the filesystem is never unmounted. While the impact is low this behavior is annoying when, for example, asssigning a static port to the lock daemon. In that case, a manual umount (and kernel module reloads, also annoying) is required.

root@host:~# mount
/dev/sda4 on / type ext3 (rw,relatime,errors=remount-ro)
proc on /proc type proc (rw,noexec,nosuid,nodev)
/sys on /sys type sysfs (rw,noexec,nosuid,nodev)
varrun on /var/run type tmpfs (rw,noexec,nosuid,nodev,mode=0755)
varlock on /var/lock type tmpfs (rw,noexec,nosuid,nodev,mode=1777)
udev on /dev type tmpfs (rw,mode=0755)
devshm on /dev/shm type tmpfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/sda1 on /boot type ext3 (rw,relatime)
/dev/sda2 on /tmp type ext3 (rw,relatime)
rpc_pipefs on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)

root@host:~# /etc/init.d/nfs-kernel-server start
 * Exporting directories for NFS kernel daemon...
   ...done.
 * Starting NFS kernel daemon
   ...done.

root@host:~# mount
/dev/sda4 on / type ext3 (rw,relatime,errors=remount-ro)
proc on /proc type proc (rw,noexec,nosuid,nodev)
/sys on /sys type sysfs (rw,noexec,nosuid,nodev)
varrun on /var/run type tmpfs (rw,noexec,nosuid,nodev,mode=0755)
varlock on /var/lock type tmpfs (rw,noexec,nosuid,nodev,mode=1777)
udev on /dev type tmpfs (rw,mode=0755)
devshm on /dev/shm type tmpfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/sda1 on /boot type ext3 (rw,relatime)
/dev/sda2 on /tmp type ext3 (rw,relatime)
rpc_pipefs on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
nfsd on /proc/fs/nfsd type nfsd (rw)

root@host:~# /etc/init.d/nfs-kernel-server stop
 * Stopping NFS kernel daemon
   ...done.
 * Unexporting directories for NFS kernel daemon...
   ...done.

root@host:~# mount
/dev/sda4 on / type ext3 (rw,relatime,errors=remount-ro)
proc on /proc type proc (rw,noexec,nosuid,nodev)
/sys on /sys type sysfs (rw,noexec,nosuid,nodev)
varrun on /var/run type tmpfs (rw,noexec,nosuid,nodev,mode=0755)
varlock on /var/lock type tmpfs (rw,noexec,nosuid,nodev,mode=1777)
udev on /dev type tmpfs (rw,mode=0755)
devshm on /dev/shm type tmpfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/sda1 on /boot type ext3 (rw,relatime)
/dev/sda2 on /tmp type ext3 (rw,relatime)
rpc_pipefs on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
nfsd on /proc/fs/nfsd type nfsd (rw)