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Re: (ITS#4168) autofs with ldap triggers segfault in kernel

On Fri, 2005-11-11 at 08:12 +0200, Buchan Milne wrote:
> On Friday 11 November 2005 01:42, ando@sys-net.it wrote:
> > On Thu, 2005-11-10 at 19:12 +0000, Guillaume.Rousse@inria.fr wrote:
> > > As noted in bugzilla report, using autofs without ldap-defined
> > > configurarion does not trigger any segfault, and rebuilding autofs
> > > against an older version of openafs lib (2.2 vs 2.3) make it works
> > > correctly.
> >
> > does the 2.2/2.3 above refer to those "openafs lib" or to OpenLDAP
> > client libraries?
> OpenLDAP only. AFAIK no openafs libs are involved, this was a typo.
> I recommended that Guillaume rebuild autofs against libldap2.2_7-devel (which 
> is currently at 2.2.27 and only retained for compatibility reasons) to see if 
> libldap was involved.
> > The description of the problem seems to indicate that 
> > the issue arises when passing from Mandriva's build of OpenLDAP
> > libraries 2.2 to 2.3
> We have only one patches on the libraries in both 2.2 and 2.3 
> (http://cvs.mandriva.com/cgi-bin/cvsweb.cgi/SPECS/openldap/openldap-2.2.19-ntlm.patch). 
> Guillaume rebuilt the 2.2 packages on the same system, and also built 2.3.11 
> (from the cooker tree), which would seem to rule out any compiler-related 
> issues.
> And note that this issue seems to only affect 64bit platforms (or at least 
> only x86_64 so far).
> > ; this may or may not disveal a problem in OpenLDAP 
> > libraries, or their misuse in the client software, or some other
> > interaction with components of the system.
> I have had reports by personal email of similar problems with samba when using 
> the pdb_ldap backend on x86_64 (whereas I use it personally on x86 with no 
> problems). Unfortunately these reporters did not post bugs or provide any 
> further information.
> I haven't been able to setup a system to reproduce this on yet (as none of my 
> x86 systems can reproduce it and I only have one x86_64 system available).
> > However, without further details, it is very unlikely we can progress
> > any further.  Can you reveal any useful info, e.g. server logs of the
> > operations (if any) that end up in the client problem?  The best would
> > be a stack backtrace of the offending OpenLDAP code, assuming that the
> > crash occurs in OpenLDAP's software.
> Since this issue affects samba only when using pdb_ldap, and autofs only when 
> using maps in LDAP, it would appear to be the case.

I'm not saying it's not.  I'm saying that right now we didn't get to a
clear indication of a bug in OpenLDAP, not to mention indications as of
where the bug could be.  The report, and your message, suggest an issue
when OpenLDAP client libraries interact with other software on certain
platforms.  The problem can be in OpenLDAP, in the client software or in
the platform.

I'm routinely developing on amd64; one issue I note is that in OpenLDAP
2.3 (as well as in late 2.2, sigh) most of the API used by autofs (after
quickly surfing the code) is deprecated, so there might be chances that
the compiler's guesses for undeclared functions conflict with the actual
arg data sizes.  I suggest you (and Guillaume) try to rebuild autofs
with LDAP_DEPRECATED explicitly defined (e.g. CPPFLAGS=-

In any case, I don't think we can easily spot the issue unless some more
details are provided.  Logs (and, for SIGSEGVs, stack backtraces)
usually are my primary inputs.


Ing. Pierangelo Masarati
Responsabile Open Solution

SysNet s.n.c.
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