autobuild[sn-devel-144]: intermittent test failure detected

[autobuild]

The autobuild test system (on sn-devel-144) has detected an intermittent failing test in 
the current master tree.

The autobuild log of the failure is available here:

   https://git.samba.org/autobuild.flakey.sn-devel-144/2018-07-27-0145/flakey.log

The failure seems to be in the "samba" suite, whose build logs are available here:

   https://git.samba.org/autobuild.flakey.sn-devel-144/2018-07-27-0145/samba.stderr
   https://git.samba.org/autobuild.flakey.sn-devel-144/2018-07-27-0145/samba.stdout
  
The top commit at the time of the failure was:

commit 4e711d18c8e9953aca2ca64179c3d0b305a41c62
Author: Ralph Boehme <slow at samba.org>
Date:   Wed Jul 25 20:02:23 2018 +0200

    smbd: don't client->connections without checking client != NULL first in exit_server_common()
    
    exit_server_common() can be called also in smbd processes without a
    smbXsrv_client structure, e.g. the parent or some background tasks.
    
    Signed-off-by: Ralph Boehme <slow at samba.org>
    Reviewed-by: Stefan Metzmacher <metze at samba.org>
    
    Autobuild-User(master): Stefan Metzmacher <metze at samba.org>
    Autobuild-Date(master): Thu Jul 26 01:29:38 CEST 2018 on sn-devel-144

and the last 50 lines of the stdout log were:

[766(4159)/889 at 51m5s] samba4.tokengroups.krb5.python(ad_dc_ntvfs)(ad_dc_ntvfs:local)
[767(4169)/889 at 51m14s] samba4.tokengroups.ntlm.python(ad_dc_ntvfs)(ad_dc_ntvfs:local)
[768(4178)/889 at 51m22s] samba4.sam.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[769(4195)/889 at 51m26s] samba4.user_account_control.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[770(4206)/889 at 51m39s] samba4.schemaInfo.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[771(4208)/889 at 51m42s] samba.tests.dsdb_schema_attributes(ad_dc_ntvfs:local)
[772(4214)/889 at 51m57s] samba4.urgent_replication.python(ad_dc_ntvfs)(ad_dc_ntvfs:local)
[773(4222)/889 at 52m0s] samba4.ldap.dirsync.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[774(4246)/889 at 53m31s] samba4.ldap.match_rules.python(ad_dc_ntvfs)
[775(4280)/889 at 53m49s] samba4.ldap.notification.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[776(4283)/889 at 53m55s] samba4.ldap.sites.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[777(4294)/889 at 54m1s] samba4.ldap.sort.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[778(4301)/889 at 54m6s] samba4.ldap.vlv.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[779(4316)/889 at 57m50s] samba4.ldap.linked_attributes.python(ad_dc_ntvfs)(ad_dc_ntvfs:local)
[780(4336)/889 at 57m54s] samba4.blackbox.ldapcmp_restore(restoredc)
[781(4337)/889 at 58m50s] samba4.blackbox.join_ldapcmp(restoredc)
[782(4339)/889 at 59m9s] samba4.blackbox.ldapcmp_restore(renamedc)
[783(4340)/889 at 59m48s] samba4.blackbox.join_ldapcmp(renamedc)
[784(4342)/889 at 1h7s] samba4.blackbox.ldapcmp_restore(labdc)
[785(4343)/889 at 1h45s] samba4.blackbox.join_ldapcmp(labdc)
[786(4345)/889 at 1h1m5s] samba4.ldap.rodc.python(rodc)(rodc)
[787(4351)/889 at 1h1m9s] samba4.ldap.rodc_rwdc.python(rodc)(rodc:local)
[788(4371)/889 at 1h8m37s] samba4.drs.replica_sync_rodc.python(rodc)(rodc:local)
[789(4373)/889 at 1h8m46s] samba4.ldap.password_settings.python(ad_dc_ntvfs)
[790(4385)/889 at 1h9m24s] samba4.ldap_schema.python(ad_dc_ntvfs)(ad_dc_ntvfs)
GSS client Update(krb5)(1) Update failed:  Miscellaneous failure (see text): Clock skew too great
UNEXPECTED(error): samba4.ldap_schema.python(ad_dc_ntvfs).__main__.SchemaTests.test_generated_linkID(ad_dc_ntvfs)
REASON: Exception: Exception: Traceback (most recent call last):
  File "/memdisk/autobuild/fl/b3541019/samba/source4/dsdb/tests/python/ldap_schema.py", line 938, in test_generated_linkID
    self.ldb.modify_ldif(ldif)
  File "bin/python/samba/__init__.py", line 241, in modify_ldif
    self.modify(msg, controls)
LdbError: (3, 'ldb_wait from (null) with LDB_WAIT_ALL: Time limit exceeded (3)')

FAILED (0 failures, 1 errors and 0 unexpected successes in 0 testsuites)

A summary with detailed information can be found in:
  ./bin/ab/summary
TOP 10 slowest tests
samba4.ldap.rodc_rwdc.python(rodc)(rodc:local) -> 448
samba4.rpc.samr.passwords.lockout on ncacn_np with (ad_dc_ntvfs) -> 226
samba4.ldap.vlv.python(ad_dc_ntvfs)(ad_dc_ntvfs) -> 224
samba4.rpc.samr.passwords.pwdlastset on ncacn_np with (ad_dc_ntvfs) -> 200
samba3.smbtorture_s3.vfs_aio_fork(simpleserver).RW2(simpleserver) -> 143
samba4.ldb.ldaps with options -U"$USERNAME%$PASSWORD"(ad_dc_ntvfs)(ad_dc_ntvfs) -> 109
samba4.raw.notify(ad_dc_ntvfs) -> 106
samba4.ldap.dirsync.python(ad_dc_ntvfs)(ad_dc_ntvfs) -> 92
samba.tests.emulate.traffic_packet(ad_dc_ntvfs) -> 70
samba.tests.samba_tool.user(ad_dc_ntvfs:local) -> 64
ERROR: test failed with exit code 1