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-144/2018-06-29-1335/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-144/2018-06-29-1335/samba.stderr
   https://git.samba.org/autobuild.flakey.sn-devel-144/2018-06-29-1335/samba.stdout
  
The top commit at the time of the failure was:

commit b6b1226d394445c21e01fdf3010642c85dbe85dd
Author: Carlos O'Donell <codonell at redhat.com>
Date:   Fri Jun 15 13:32:46 2018 +0200

    ctdb: Improve robust mutex test
    
    This avoids some of the undefined behaviour, like initializing the same mutex
    twice which happens when the low and high priority processes start (both
    do the initialization and that's dangerous.) Instead now we start an
    "init" process to start the shared memory segment, and then everything
    else just uses it without truncation or unlinking (same mutex).
    
    Signed-off-by: Carlos O'Donell <codonell at redhat.com>
    Reviewed-by: Andreas Schneider <asn at samba.org>
    Reviewed-by: Amitay Isaacs <amitay at gmail.com>
    
    Autobuild-User(master): Amitay Isaacs <amitay at samba.org>
    Autobuild-Date(master): Fri Jun 29 06:47:00 CEST 2018 on sn-devel-144

and the last 50 lines of the stdout log were:

[757(4064)/855 at 53m11s] samba.tests.blackbox.traffic_replay(ad_dc_ntvfs)
[758(4070)/855 at 53m21s] samba.tests.blackbox.traffic_learner(ad_dc_ntvfs)
[759(4072)/855 at 53m21s] samba.tests.blackbox.traffic_summary(ad_dc_ntvfs)
[760(4072)/855 at 53m21s] samba.tests.blackbox.smbcontrol(ad_dc_ntvfs:local)
[761(4074)/855 at 53m23s] samba.tests.blackbox.smbcontrol(promoted_dc:local)
[762(4076)/855 at 53m24s] samba4.ldap.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[763(4115)/855 at 53m35s] samba4.tokengroups.krb5.python(ad_dc_ntvfs)(ad_dc_ntvfs:local)
[764(4125)/855 at 53m43s] samba4.tokengroups.ntlm.python(ad_dc_ntvfs)(ad_dc_ntvfs:local)
[765(4134)/855 at 53m51s] samba4.sam.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[766(4151)/855 at 53m55s] samba4.user_account_control.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[767(4162)/855 at 54m8s] samba4.schemaInfo.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[768(4164)/855 at 54m11s] samba.tests.dsdb_schema_attributes(ad_dc_ntvfs:local)
[769(4170)/855 at 54m25s] samba4.urgent_replication.python(ad_dc_ntvfs)(ad_dc_ntvfs:local)
[770(4178)/855 at 54m28s] samba4.ldap.dirsync.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[771(4202)/855 at 56m2s] samba4.ldap.match_rules.python(ad_dc_ntvfs)
[772(4236)/855 at 56m20s] samba4.ldap.notification.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[773(4239)/855 at 56m31s] samba4.ldap.sites.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[774(4250)/855 at 56m37s] samba4.ldap.sort.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[775(4257)/855 at 56m42s] samba4.ldap.vlv.python(ad_dc_ntvfs)(ad_dc_ntvfs)
[776(4272)/855 at 1h24s] samba4.ldap.linked_attributes.python(ad_dc_ntvfs)(ad_dc_ntvfs:local)
[777(4292)/855 at 1h29s] samba4.ldap.rodc.python(rodc)(rodc)
[778(4298)/855 at 1h33s] samba4.ldap.rodc_rwdc.python(rodc)(rodc:local)
[779(4318)/855 at 1h7m49s] samba4.drs.replica_sync_rodc.python(rodc)(rodc:local)
[780(4320)/855 at 1h7m57s] samba4.ldap.password_settings.python(ad_dc_ntvfs)
[781(4332)/855 at 1h8m36s] 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_mAPIID(ad_dc_ntvfs)
REASON: Exception: Exception: Traceback (most recent call last):
  File "/memdisk/autobuild/fl/b2562987/samba/source4/dsdb/tests/python/ldap_schema.py", line 1173, in test_generated_mAPIID
    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) -> 437
samba4.rpc.samr.passwords.lockout on ncacn_np with (ad_dc_ntvfs) -> 227
samba4.ldap.vlv.python(ad_dc_ntvfs)(ad_dc_ntvfs) -> 222
samba4.rpc.samr.passwords.pwdlastset on ncacn_np with (ad_dc_ntvfs) -> 203
samba3.smbtorture_s3.vfs_aio_fork(simpleserver).RW2(simpleserver) -> 136
samba4.ldb.ldaps with options -U"$USERNAME%$PASSWORD"(ad_dc_ntvfs)(ad_dc_ntvfs) -> 116
samba4.raw.notify(ad_dc_ntvfs) -> 107
samba4.ldap.dirsync.python(ad_dc_ntvfs)(ad_dc_ntvfs) -> 94
samba.tests.emulate.traffic_packet(ad_dc_ntvfs) -> 69
samba.tests.samba_tool.user(ad_dc_ntvfs:local) -> 66
ERROR: test failed with exit code 1