Description of problem:

This a bug report follow up to investigate a LDAP memory leak in RHEL-8.5.0 IPA context, from a preliminary investigation by Thierry B.:

 - One leak in ipa plugin ipa-cldap. This is by far the larger one and likely the
   the main concern of the customer
Direct leak of 28798 byte(s) in 238 object(s) allocated from:
    #0 0x7f32ad890ba8 in __interceptor_malloc (/usr/lib64/libasan.so.5+0xefba8)
    #1 0x7f329b3317b5 in ipa_cldap_netlogon (/usr/lib64/dirsrv/plugins/libipa_cldap.so+0x47b5)
    #2 0x7f329b331d80 in ipa_cldap_worker (/usr/lib64/dirsrv/plugins/libipa_cldap.so+0x4d80)
    #3 0x7f32a9886179 in start_thread (/lib64/libpthread.so.0+0x8179)
    #4 0x7f32abbf7dc2 in __clone (/lib64/libc.so.6+0xfcdc2)


Steps to Reproduce:

1. N/A
debuginfo and libasan were installed, dirsrv systemd service drop-in config file created, and /run/dirsrv/ns-slapd*asan* files collected and reviewed


Additional info:

oom seen in /var/log/messages

Dec  6 15:16:53 eqds3tfrmipa001 kernel: ns-slapd invoked oom-killer: gfp_mask=0x201da, order=0, oom_score_adj=0
Dec  6 15:16:53 eqds3tfrmipa001 kernel: [<ffffffff98997904>] oom_kill_process+0x254/0x3d0
Dec  6 15:16:53 eqds3tfrmipa001 kernel: [<ffffffff989973ad>] ? oom_unkillable_task+0xcd/0x120
Dec  6 15:16:54 eqds3tfrmipa001 kernel: [ pid ]   uid  tgid total_vm      rss nr_ptes swapents oom_score_adj name


RHEL-8.5

389-ds-base-1.4.3.23-10.module+el8.5.0+12398+47000435.x86_64 Thu Dec  9 11:14:38 2021
ipa-server-4.9.6-6.module+el8.5.0+12660+88e16a2c.x86_64     Thu Dec  9 11:15:00 2021
redhat-release-8.5-0.8.el8.x86_64                           Thu Dec  9 11:15:33 2021
slapi-nis-0.56.6-4.module+el8.5.0+12583+bf7ffcf6.x86_64     Thu Dec  9 11:14:39 2021