During net ads join we got a problem with kerberos keytab creation.

# net ads join -k
Failed to join domain: failed to create kerberos keytab

In gdb It looks like this:

# gdb net
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Reading symbols from net...Reading symbols from /usr/lib/debug/usr/bin/net.debug...done.
done.
(gdb) break ads_keytab_create_default
Function "ads_keytab_create_default" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (ads_keytab_create_default) pending.
(gdb) break ads_keytab_add_entry
Function "ads_keytab_add_entry" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 2 (ads_keytab_add_entry) pending.
(gdb) run ads join -k
Starting program: /usr/bin/net ads join -k
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Detaching after fork from child process 24845.
Missing separate debuginfo for /lib64/libnss_mdns4_minimal.so.2
Try to install the hash file /usr/lib/debug/.build-id/ca/b39d28abba0e34ad5e8b46c840e843a8b8c2bf.debug
Missing separate debuginfo for /lib64/libnss_dns.so.2
Try to install the hash file /usr/lib/debug/.build-id/13/ff5c47493975a171a5f9f4fac7e77bcae20ecd.debug
Missing separate debuginfo for /usr/lib64/krb5/plugins/libkrb5/sssd_krb5_locator_plugin.so
Try to install the hash file /usr/lib/debug/.build-id/de/efb280e101d9716e0e580f067ab04f822369df.debug
Missing separate debuginfo for /usr/lib64/gconv/IBM850.so
Try to install the hash file /usr/lib/debug/.build-id/89/921a4768b80b4cc484dc88385a637944747f8b.debug
Missing separate debuginfo for /usr/lib64/gconv/UTF-16.so
Try to install the hash file /usr/lib/debug/.build-id/0d/5c6739221650099f20ac27dc648e9aaa9067b6.debug
Missing separate debuginfo for /lib64/libnss_myhostname.so.2
Try to install the hash file /usr/lib/debug/.build-id/4b/370f6107d1a4b56cf6d404684890cbbd8ba0f0.debug
Missing separate debuginfo for /lib64/libnss_fallback.so.2
Try to install the hash file /usr/lib/debug/.build-id/74/bf6740821bdecda694512ab57406a5c86a2c9e.debug
Missing separate debuginfo for /lib64/libnss_mymachines.so.2
Try to install the hash file /usr/lib/debug/.build-id/3b/ccd4619a5e1ed1ebddbbbba901d908e3eb8da1.debug

Breakpoint 1, ads_keytab_create_default (ads=0x5555558512d0) at ../source3/libads/kerberos_keytab.c:314
314     {
(gdb) c
Continuing.

Breakpoint 2, ads_keytab_add_entry (ads=ads@entry=0x5555558512d0, srvPrinc=srvPrinc@entry=0x555555853f60 "host") at ../source3/libads/kerberos_keytab.c:42
42      {
(gdb) n
44              krb5_context context = NULL;
(gdb) 
45              krb5_keytab keytab = NULL;
(gdb) 
48              krb5_enctype enctypes[6] = {
(gdb) 
70              initialize_krb5_error_table();
(gdb) 
71              ret = krb5_init_context(&context);
(gdb) 
72              if (ret) {
(gdb) display krb5_init_context
1: krb5_init_context = {krb5_error_code (krb5_context *)} 0x7ffff1065ea0 <krb5_init_context>
(gdb) display ret
2: ret = 1434813424
(gdb) n
78              ret = smb_krb5_kt_open(context, NULL, True, &keytab);
2: ret = 1434813424
1: krb5_init_context = {krb5_error_code (krb5_context *)} 0x7ffff1065ea0 <krb5_init_context>
(gdb) n
79              if (ret) {
2: ret = 1434813424
1: krb5_init_context = {krb5_error_code (krb5_context *)} 0x7ffff1065ea0 <krb5_init_context>
(gdb) n
78              ret = smb_krb5_kt_open(context, NULL, True, &keytab);
2: ret = 1434813424
1: krb5_init_context = {krb5_error_code (krb5_context *)} 0x7ffff1065ea0 <krb5_init_context>
(gdb) n
79              if (ret) {
2: ret = -1765328205
1: krb5_init_context = {krb5_error_code (krb5_context *)} 0x7ffff1065ea0 <krb5_init_context>
(gdb) n
80                      DEBUG(1, ("smb_krb5_kt_open failed (%s)\n",
2: ret = -1765328205
1: krb5_init_context = {krb5_error_code (krb5_context *)} 0x7ffff1065ea0 <krb5_init_context>
(gdb)

Main problem got from commit e0990ccf4e68a8d1bdce

commit e0990ccf4e68a8d1bdce89b7d83865d950b4c4d0
Author: Andreas Schneider <asn@samba.org>
Date:   Wed Dec 14 16:37:17 2016 +0100

    krb5_wrap: More checks for absolute path in smb_krb5_kt_open()

Attached patch resolve this problem.