https://bugs.openldap.org/show_bug.cgi?id=9924
--- Comment #10 from Howard Chu hyc@openldap.org --- (In reply to Howard Chu from comment #3)
You need to also use the valgrind option --keep-debuginfo=yes otherwise the symbols for dynamically loaded modules are lost when they're unloaded at slapd shutdown time.
(Reminded me that we worked over 14 years to get this option added to valgrind... https://bugs.kde.org/show_bug.cgi?id=79362 )