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-144/2018-04-11-1249/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-144/2018-04-11-1249/samba.stderr
   https://git.samba.org/autobuild.flakey.sn-devel-144/2018-04-11-1249/samba.stdout
  
The top commit at the time of the failure was:

commit 462eb4a44cc51dc17aebbcd5c609c9ff7f088554
Author: Andrew Bartlett <abartlet at samba.org>
Date:   Tue Apr 10 16:37:45 2018 +1200

    lib/util: Call log_stack_trace() in smb_panic_default()
    
    This matches the AD DC with the behaviour in smbd.
    
    Signed-off-by: Andrew Bartlett <abartlet at samba.org>
    Reviewed-by: Jeremy Allison <jra at samba.org>
    
    Autobuild-User(master): Jeremy Allison <jra at samba.org>
    Autobuild-Date(master): Wed Apr 11 04:03:07 CEST 2018 on sn-devel-144

and the last 50 lines of the stdout log were:

[64(142)/831 at 6m6s] samba3.blackbox.smbclient_ntlm.plain (maptoguest)(maptoguest)
[65(155)/831 at 6m9s] samba3.raw.samba3hide(simpleserver)
[66(156)/831 at 6m10s] samba3.raw.samba3checkfsp(simpleserver)
[67(157)/831 at 6m12s] samba3.raw.samba3closeerr(simpleserver)
[68(158)/831 at 6m14s] samba3.smb2.change_notify_disabled(simpleserver)
[69(159)/831 at 6m14s] samba3.smb2.dosmode(simpleserver)
[70(160)/831 at 6m14s] samba3.rpc.schannel_anon_setpw anonymous password set (schannel enforced server-side)(nt4_dc_schannel)
[71(161)/831 at 6m14s] idmap.rfc2307(ad_member_rfc2307)
[72(320)/831 at 7m46s] idmap.alloc(ad_member_rfc2307)
[73(322)/831 at 7m48s] samba3.rpc.lsa.lookupsids krb5 with old ccache ncacn_np with [smb2] (ktest)
[74(323)/831 at 7m49s] samba3.rpc.lsa.lookupsids krb5 ncacn_np with [smb2] (ktest)
[75(324)/831 at 7m49s] samba3.blackbox.rpcclient krb5 ncacn_np with [krb5] (ktest:local)
[76(325)/831 at 7m49s] samba3.blackbox.rpcclient krb5 ncacn_np with [spnego,krb5] (ktest:local)
[77(326)/831 at 7m50s] samba3.rpc.lsa.lookupsids krb5 with old ccache ncacn_np with [smb2,connect] (ktest)
[78(327)/831 at 7m50s] samba3.rpc.lsa.lookupsids krb5 ncacn_np with [smb2,connect] (ktest)
[79(328)/831 at 7m51s] samba3.blackbox.rpcclient krb5 ncacn_np with [krb5,connect] (ktest:local)
[80(329)/831 at 7m51s] samba3.blackbox.rpcclient krb5 ncacn_np with [spnego,krb5,connect] (ktest:local)
[81(330)/831 at 7m51s] samba3.rpc.lsa.lookupsids krb5 with old ccache ncacn_np with [smb2,packet] (ktest)
[82(331)/831 at 7m52s] samba3.rpc.lsa.lookupsids krb5 ncacn_np with [smb2,packet] (ktest)
[83(332)/831 at 7m52s] samba3.blackbox.rpcclient krb5 ncacn_np with [krb5,packet] (ktest:local)
[84(333)/831 at 7m53s] samba3.blackbox.rpcclient krb5 ncacn_np with [spnego,krb5,packet] (ktest:local)
[85(334)/831 at 7m53s] samba3.rpc.lsa.lookupsids krb5 with old ccache ncacn_np with [smb2,sign] (ktest)
[86(335)/831 at 7m53s] samba3.rpc.lsa.lookupsids krb5 ncacn_np with [smb2,sign] (ktest)
[87(336)/831 at 7m54s] samba3.blackbox.rpcclient krb5 ncacn_np with [krb5,sign] (ktest:local)
[88(337)/831 at 7m54s] samba3.blackbox.rpcclient krb5 ncacn_np with [spnego,krb5,sign] (ktest:local)
[89(338)/831 at 7m54s] samba3.rpc.lsa.lookupsids krb5 with old ccache ncacn_np with [smb2,seal] (ktest)
[90(339)/831 at 7m55s] samba3.rpc.lsa.lookupsids krb5 ncacn_np with [smb2,seal] (ktest)
[91(340)/831 at 7m55s] samba3.blackbox.rpcclient krb5 ncacn_np with [krb5,seal] (ktest:local)
[92(341)/831 at 7m55s] samba3.blackbox.rpcclient krb5 ncacn_np with [spnego,krb5,seal] (ktest:local)
[93(342)/831 at 7m56s] samba3.blackbox.sharesec(simpleserver:local)
[94(377)/831 at 7m58s] samba3.blackbox.net_tdb(simpleserver:local)
UNEXPECTED(failure): samba3.blackbox.net_tdb.Looking for open file in locking.tdb(simpleserver:local)
REASON: Exception: Exception: Invalid length of key

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

A summary with detailed information can be found in:
  ./bin/ab/summary
TOP 10 slowest tests
samba3.smbtorture_s3.vfs_aio_fork(simpleserver).RW2(simpleserver) -> 153
idmap.rfc2307(ad_member_rfc2307) -> 81
samba3.smbtorture_s3.plain(ad_dc_ntvfs).LOCK1(ad_dc_ntvfs) -> 20
samba3.smbtorture_s3.plain(ad_dc_ntvfs).IOCTL(ad_dc_ntvfs) -> 10
samba3.smbtorture_s3.vfs_aio_fork(simpleserver).RW1(simpleserver) -> 8
samba.tests.messaging.python3(ad_dc_ntvfs:local) -> 7
samba3.blackbox.smbclient_ntlm.plain (s4member)(s4member) -> 6
samba3.smbtorture_s3.plain(ad_dc_ntvfs).TRANS2(ad_dc_ntvfs) -> 6
samba3.blackbox.smbclient_auth.plain (maptoguest) local creds(maptoguest) -> 4
samba3.blackbox.smbclient_ntlm.plain (maptoguest)(maptoguest) -> 4
ERROR: test failed with exit code 1