problem: ac_shell and ldap user

[Johannes Wolkerstorfer]

We have a problem running the Cadence pks_shell synthesizer under Redhat
8.0: It will produce a segmentation fault and prompt:

"==> ERROR: An unrecoverable exception has occurred (SEGV)."

This is not a generell problem because other Cadence software products (e.g.
ncsim) run without any problem.

We use the following versions:
pks_shell: @(#)CDS: pks_shell v05.10-s071+2 (32bit) 06/03/03 02:28
(Linux 2.4)
RedHat: Linux version 2.4.18-14
(bhcompile@stripples.devel.redhat.com) (gcc version 3.2 20020903 (Red Hat
Linux 8.0 3.2-7)) #1 Wed Sep 4 13:35:50 EDT 2002

The problem seems to be related to LDAP users: running pks_shell as root
works fine because the root user is defined in local files (/etc/passwd,
/etc/shadow). All other users are LDAP users who face the problem described
above. The assumption that LDAP causes the problem stems from tracing the
execution of pks_shell by the "strace" tool which monitors system calls.

We have also verified that all relevant files for user authentication and
DNS are readable by normal users to eliminate a trivial cause for the
problems described: /etc/nsswitch.conf, /etc/resolv.conf,
/etc/ldap.conf, /etc/passwd. The shared objects in use (.so files) have
read and execution rights for normal users too.

So we assume that the segmentation fault might be caused by a programming
error. Has somebody else faced this problem? Or even has got a solution for
it?

Kind regards and Thanks in advance,
Johannes Wolkerstorfer

----------------------------------------------------------------
Johannes Wolkerstorfer <Johannes.Wolkerstorfer@iaik.tugraz.at>
Institute for Applied Information Processing and Communications,
Graz University of Technology, Inffeldg. 16a, 8010 Graz, Austria
tel: +43 316 873-5515 fax: +43 316 873-5520 http://www.iaik.at

 

[Johannes Wolkerstorfer]

Finally, we have found a way to prevent the described failure:

Running the "nscd" daemon avoids the segmentation fault.

NSCD seems to be the solution to the problem. NSCD caches nameservice
requests (the nameservice itself is configured via nsswitch.conf).

-- Johannes Wolkerstorfer.

Johannes Wolkerstorfer wrote:

We have a problem running the Cadence pks_shell synthesizer under
Redhat
8.0: It will produce a segmentation fault and prompt:

"==> ERROR: An unrecoverable exception has occurred (SEGV)."

This is not a generell problem because other Cadence software
products (e.g. ncsim) run without any problem.

We use the following versions:
pks_shell: @(#)CDS: pks_shell v05.10-s071+2 (32bit) 06/03/03
02:28 (Linux 2.4)
RedHat: Linux version 2.4.18-14
(bhcompile@stripples.devel.redhat.com) (gcc version 3.2 20020903 (Red
Hat Linux 8.0 3.2-7)) #1 Wed Sep 4 13:35:50 EDT 2002

The problem seems to be related to LDAP users: running pks_shell as
root works fine because the root user is defined in local files
(/etc/passwd, /etc/shadow). All other users are LDAP users who face
the problem described above. The assumption that LDAP causes the
problem stems from tracing the execution of pks_shell by the "strace"
tool which monitors system calls.

We have also verified that all relevant files for user authentication
and DNS are readable by normal users to eliminate a trivial cause for
the problems described: /etc/nsswitch.conf, /etc/resolv.conf,
/etc/ldap.conf, /etc/passwd. The shared objects in use (.so files)
have read and execution rights for normal users too.

So we assume that the segmentation fault might be caused by a
programming error. Has somebody else faced this problem? Or even has
got a solution for it?

Kind regards and Thanks in advance,
Johannes Wolkerstorfer

----------------------------------------------------------------
Johannes Wolkerstorfer <Johannes.Wolkerstorfer@iaik.tugraz.at
Institute for Applied Information Processing and Communications,
Graz University of Technology, Inffeldg. 16a, 8010 Graz, Austria
tel: +43 316 873-5515 fax: +43 316 873-5520 http://www.iaik.at