Description of problem:
 The named-sdb utility can raise an abort within ldapdb_getconn() due to a seeming double-free condition. This only occurs on process stop. The representative backtrace for this failure is:

	#0  0x00007fa5c9e275e5 in raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
	#1  0x00007fa5c9e28dc5 in abort () at abort.c:92
	#2  0x00007fa5c9e654f7 in __libc_message (do_abort=2, fmt=0x7fa5c9f4da60 "*** glibc detected *** %s: %s: 0x%s ***\n") at ../sysdeps/unix/sysv/linux/libc_fatal.c:198
	#3  0x00007fa5c9e6af3e in malloc_printerr (action=3, str=0x7fa5c9f4ddd0 "double free or corruption (out)", ptr=<value optimized out>, ar_ptr=<value optimized out>) at malloc.c:6360
	#4  0x00007fa5c9e6ddd0 in _int_free (av=0x7fa5ca183120, p=0x7fa5cd461060, have_lock=0) at malloc.c:4846
	#5  0x00007fa5cd565a68 in ldapdb_getconn (data=0x0) at ldapdb.c:137
	#6  0x00007fa5cd565ba5 in ldapdb_clear () at ldapdb.c:665
	#7  0x00007fa5cd51e22f in cleanup (argc=<value optimized out>, argv=0x7fff03fb7308) at ./main.c:1010
	#8  main (argc=<value optimized out>, argv=0x7fff03fb7308) at ./main.c:1198

 The relevant source snippet is:

	132			while (allthreadsdata != NULL) {
	133				threaddata = allthreadsdata;
	134				free(threaddata->index);
	135				while (threaddata->data != NULL) {
	136					conndata = threaddata->data;
	137					free(conndata->index);         # This operation
	138					if (conndata->data != NULL)
	139						ldap_unbind((LDAP *)conndata->data);
	140					threaddata->data = conndata->next;
	141					free(conndata);


Version-Release number of selected component (if applicable):
 bind-9.8.2-0.47.rc1.el6_8.3.x86_64


How reproducible:
 Everytime for the end system impacted. Unable to reproduce the same condition

Steps to Reproduce:
1. On a system susceptible to the issue, start named-sdb
2. Stop named-sdb
3.

Actual results:
 The application exits with an abort() related to a glibc detected double-free

Expected results:
 Exits successfully

Additional info: