On my x86_64 box running Fedora Core 3, net segfaults when attempting to join an
ADS domain.

[root@smbserver ~]# gdb net
GNU gdb Red Hat Linux (6.1post-1.20040607.43rh)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu"...Using host libthread_db
library "/lib64/tls/libthread_db.so.1".
 
(gdb) run ads join -U administrator@domain.com
Starting program: /usr/bin/net ads join -U administrator@domain.com
administrator@domain.com's password:
[2004/11/15 11:49:42, 0] libads/ldap.c:ads_add_machine_acct(1366)
  ads_add_machine_acct: Host account for smbserver already exists - modifying
old account
 
Program received signal SIGSEGV, Segmentation fault.
0x0000002a96092590 in ldap_msgfree () from /usr/lib64/libldap-2.2.so.7
(gdb) bt
#0  0x0000002a96092590 in ldap_msgfree () from /usr/lib64/libldap-2.2.so.7
#1  0x000000552abea625 in ads_workgroup_name (ads=0x552ae2b550,
mem_ctx=0x552ae303a0, workgroup=0x7fbffff168) at libads/ldap.c:2508
#2  0x000000552aaeb565 in net_ads_join (argc=0, argv=0x5500000000) at
utils/net_ads.c:795
#3  0x000000552aaec965 in net_ads (argc=1, argv=0x552ad84330) at
utils/net_ads.c:1479
#4  0x000000552aae9bf0 in main (argc=5, argv=0x7fbffff9b8) at utils/net.c:849
(gdb)

I did try removing the existing computer account up front, but with same result.

Please let me know if i can try/provide you with something else.