kernel automounter does not unmount

["Thomas Gebhardt" <gebhardt@HRZ.Uni-Marburg.DE>]

Hi,

several times I got the problem that a huge amount of home directories
are mounted by the kernel automounter

# df | wc -l
   1647

Some directories are mounted several times. It seems that these
directories are not accessed (lsof shows no file access to these
directories). I cannot unmount these directories manually (no
error message but the mount persists). I have not yet found any
solution but to reboot the system.

Could anyone give me a hint how to figure out what's going on here?
Since autofs hides in kernel space I don't know how to analyze
the situation.

Thanks!

My system: Debian/woody (autofs 3.9.99-4.0.0pre10-1)
Kernel 2.4.20 with grsecurity patches:
# grep AUTOFS /boot/config-2.4.20-grsec
CONFIG_AUTOFS_FS=m
CONFIG_AUTOFS4_FS=m

NFS Server is an AIX machine.

Cheers, Thomas