Crashes in ldap_unbind

Hi All,

We have a multi-threaded server that uses netscape ldap c sdk 4.1 in
it's older release. We are experiencing some random crashes, while
freeing memory, in the call to ldap_unbind() in our code. Due to its
random nature, We haven't been able to create a test case for the
issue so far. 

Our environment is as follows

- The backend directory server is AD.NET 2003 and our server is
running on a Win 2003 box. AD.NET is by default configured to close
idle ldap connections every 15 mins.
- ldap sdk version is 4.1. [We have alread migrated to ldap sdk 5.X in
the later versions of our product.]
- Another thing that is hampering us is that there are no Windows
symbol files[pdb] available for ldap sdk 4.1, which prevents us from
capturing an exact stacktrace inside ldap_unbind.
- Our server creates a pool of ldap connections with separate
dedicated threads to create new connections as well as clean-up old
connections.
- multiple worker threads can share the same ldap connection handle at
the same time. e.g. you can have multiple ldap_simple_bind going
asynchronously over the same ldap connection handle at the same time.
- we have registered callback functions for createmutex, lockmutex,
unlockmutex, freemutex, getthreadid, getldaperror etc.
- we have confirmed via logging that we are not calling ldap_unbind
twice on the same ldap handle.

Please let me know if anyone has any suggestions. 

I also noticed that there were already a couple of posts regarding
crashes in ldap_unbind. Did we have any resolutions for these?

Heroux, Bernard R wrote on 3/30/2006
> Every so often the ldap_unbind_s will cause a crash.  This occurs even 
> when checking the ldapHandle for NULL before calling the unbind.

Mike wrote on 3/2/2006
> I was reading through the documentation on how to handle failover or 
> being disconnected from an LDAP server in my apps.  One method is to 
> call ldap_unbind and reconnect and rebind, while the other method is set 
> the LDAP_OPT_RECONNECT option and only rebind (i.e. don't call 
> ldap_unbind).
>
> http://www.mozilla.org/directory/csdk-docs/using.htm#handle_failover
>
> We had been using the former of the two methods, but some of our apps 
> were coring randomly during the ldap_unbind call

Thanks & Regards,
Pradnyesh