ADSM-L

Re: SunOS error: ANS4510E Error allocating semaphores ??

1998-09-14 12:53:01
Subject: Re: SunOS error: ANS4510E Error allocating semaphores ??
From: "Thomas A. La Porte" <tlaporte AT ANIM.DREAMWORKS DOT COM>
Date: Mon, 14 Sep 1998 09:53:01 -0700
Ole,

The issue here is primarily one of security. For non-root users,
the ADSM client uses a trusted client (dsmtca) process to
communicate with the ADSM server. This dsmtca process runs setuid
root, and communicates with the user process (dsmc) via shared
memory, which requires the use of semaphores. Most OSes have a
kernel tunable parameter that establishes a maximum limit on the
amount of shared memory, and the amount of semaphores, that can
be used in a system. Your users are obviously reaching this
maximum.

This could be caused by running many non-root dsmc processes at
once, or by non-root dsmc processes that were terminated
improperly which have not had there shared memory resources freed
up by the OS. We have seen this second problem before under
Irix 6.2. You can use the 'ipcs' command to view information
about shared memory (inter-process communication). 'ipcs -sa'
will give full information about all allocated semaphores.

It would be difficult to guess why you are only now seeing this
occurrence. My best guess is that it is neither a change to the
ADSM code nor a change to the OS configuration, but a change in
usage patterns. Perhaps more non-root users are using ADSM, or
perhaps a single non-root user is ending a series of ADSM
sessions with 'Ctrl-C' or 'kill -9'.

 -- Tom

Thomas A. La Porte
DreamWorks Feature Animation
tlaporte AT anim.dreamworks DOT com

On Mon, 14 Sep 1998, Ole Holm Nielsen wrote:

>For quite a while our ADSM V2R1 client running on SunOS 4.1.3
>has been making a stupid error message, which I guess to be a
>bug in the ADSM client:
>
># dsmc
>ADSTAR Distributed Storage Manager
>Command Line Backup Client Interface - Version 2, Release 1, Level 0.8
>(C) Copyright IBM Corporation, 1990, 1997, All Rights Reserved.
>
>dsmc> q vol
>ANS4510E Error allocating semaphores.
>
>---
>
>This is for an ordinary user, for root there is no problem
>with dsmc, but the graphical tool dsm still doesn't work.
>So the backup client is completely useless :-(  Fortunately,
>backups done by "root" are working OK.
>
>This used to work with some earlier ADSM client version, and
>the SunOS 4.1.3 server is in a frozen configuration, so I do
>not think that the problem is due to OS changes (but who knows
>for sure :-).
>
>Does anyone know a workaround for this "semaphores" problem,
>and perhaps the cause ?
>
>Thanks a lot,
>Ole H. Nielsen
>Department of Physics, Building 307
>Technical University of Denmark, DK-2800 Lyngby, Denmark
>E-mail: mailto:Ole.H.Nielsen AT fysik.dtu DOT dk
>WWW URL: http://www.fysik.dtu.dk/persons/ohnielse.html
>Telephone: (+45) 45 25 31 87 / Telefax: (+45) 45 93 23 99
>
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