SUMMARY: unmounting /cdrom

From: Randy Bush (
Date: Sun Oct 23 1994 - 05:26:14 CDT

The question:

   When an rsh process from another host (a BSDI install) has accessed a
   mounted /cdrom, I am not able to later umount it. umount reports device
   busy though the using process is long gone.

   How do I force a umount?

The answer:

   Reboot <grrrrr>.

From: (Mike Phillips 3788)

I suspect that an in.rshd or that a <zombie> process has been left hanging
around if it's a in.rshd just kill it if it's a <zombie> process your stuck.
I had a similiar situation with a zombie process the other day only way out
was to reboot my server OOuch :-((

From: (David Warm)

Try umount -f.

From: (Markus Buchhorn)

The two things I've seen cause a problem like this are:

(i) File Manager - somebodies fm has picked up that the cdrom was mounted
and is displaying it for that user. This causes umount to see the drive as
'busy'. Check the process table for anybody running filemanager.

(ii) running some/any setuid program during the time that the cdrom was
mounted, or some other curious user has come along and looked at the drive,
and so I can't readily find it in the process table. Under SunOS 4.1.x you
can use the -E switch to ps (together with -wwww) to see the environment of
every process, then grep this for the cdrom. I don't think there is such an
option for Solaris 2.x, which I consider a serious misfeature/bug !

From: Guy Polis <>

Try wrapping the script that get's rsh'd with 'script' to decouple all
controlling terminals and such.

i.e. script to run = "cd_mount"

     SHELL=cd_mount script /dev/null (or a file, to retain it)

From: (Perry Hutchison)

Barring a bug, if umount says the device is busy there is still some process
which has a file open on it or has its current directory there. The only
way I know of is to use something like "ofiles" or "lsof" to find the
process, then kill it. If such a process is hung in a non-interruptable
state (D in the ps listing) it is usually necessary to reboot.

From: David R Courtade <>

Be sure you are not in the /cdrom directory. The umount will give this
message if you are in the mount point you are trying to umount.

From: Steve Lacey <>

This is a known problem with the BSDI cdrom itself when mounted on a
Sun. Not sure about the exact cause, but the only method of umount I've
found is reboot...

From: (Zenon Dewicki ph3580)

All nodes that may have accessed (mounted) the cdrom must umount before the
cdrom can be unmounted.

From: (Mark S. Anderson)

Are you using Solaris 2.3? If so, just type "eject cdrom"

[ nah, I'm using UNIX -- rb ]

From: "Michael (M.A.) Meystel" <MEYSTMA%DUVM.BITNET@pucc.Princeton.EDU>

Have you tried removing the mnttab entry?

That usually works.

But this sounds like a bug to me; I have worked around this problem by
manually editing /etc/mnttab but this is a disgusting way to fix the

Incidentally, this is under Solaris 2.3, I'm talking about. You didn't
mention the OS that you're running.

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