Re: (ITS#8897) Delta syncrepl + refreshOnly segfault if 2 servers receive same group modification operation within interval

[Mark.Cairney@ed.ac.uk]

Hi Quanah,

It certainly sounds very similar from the description.
I've applied the patch on our Dev systems and tried to recreate the
crash but this time they don't crash and the change appears to make it
to all 4 servers.

Based on that I'm happy to close it as a duplicate.

For completeness here's the log snippet from one of the 2 servers not to
get the change directly:

2018-08-13T15:51:41.309019+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: conn=2891 op=1 SEARCH RESULT tag=101 err=0 nentries=0 text=
2018-08-13T15:51:41.310958+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: conn=2891 op=2 UNBIND
2018-08-13T15:51:41.311320+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: conn=2891 fd=17 closed
2018-08-13T15:52:18.347529+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: do_syncrep2: rid=003
cookie=rid=003,sid=00a,csn=20180810152745.105428Z#000000#009#000000
2018-08-13T15:52:18.347925+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: do_syncrep2: rid=003 CSN too old, ignoring
20180810152745.105428Z#000000#009#000000
(reqStart=20180810152801.000001Z,cn=accesslog)
2018-08-13T15:52:19.361612+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: do_syncrep2: rid=004
cookie=rid=004,sid=00c,csn=20180813145040.294725Z#000000#00c#000000
2018-08-13T15:52:19.361936+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: slap_queue_csn: queueing 0x4279380
20180813145040.294725Z#000000#00c#000000
2018-08-13T15:52:19.362187+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: syncrepl_message_to_op: rid=004 tid 6f1f6700
2018-08-13T15:52:19.378677+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: slap_queue_csn: queueing 0x3e067c0
20180813145040.294725Z#000000#00c#000000
2018-08-13T15:52:19.380316+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: slap_graduate_commit_csn: removing 0x3e067c0
20180813145040.294725Z#000000#00c#000000
2018-08-13T15:52:19.380570+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: slap_graduate_commit_csn: removing 0x4279380
20180813145040.294725Z#000000#00c#000000
2018-08-13T15:52:19.380819+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: syncrepl_message_to_op: rid=004 be_modify
uid=jaw,ou=people,ou=central,dc=authorise-dev,dc=ed,dc=ac,dc=uk (0)
2018-08-13T15:52:19.381044+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: slap_queue_csn: queueing 0x419d5c0
20180813145040.294725Z#000000#00c#000000
2018-08-13T15:52:19.385145+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: slap_graduate_commit_csn: removing 0x419d5c0
20180813145040.294725Z#000000#00c#000000
2018-08-13T15:52:19.385403+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: do_syncrep2: rid=004 LDAP_RES_SEARCH_RESULT
2018-08-13T15:52:19.385654+01:00 bonsai.authorise-dev.is.ed.ac.uk
slapd[33415]: do_syncrep2: rid=004
cookie=rid=004,sid=00c,csn=20120217162731.749366Z#000000#000#000000;20180701051000.119854Z#000000#003#000000;20180711011500.114848Z#000000#004#000000;20180710075708.402194Z#000000#005#000000;20180703112408.905121Z#000000#006#000000;20180813144557.086593Z#000000#009#000000;20180813145034.034818Z#000000#00b#000000;20180813145040.294725Z#000000#00c#000000


Kind regards,
Mark

On 10/08/18 17:00, Quanah Gibson-Mount wrote:
> --On Friday, August 10, 2018 4:41 PM +0000 Mark.Cairney@ed.ac.uk wrote:
> 
>> Full_Name: Mark Cairney
>> Version: 2.4.46
>> OS: Centos 7
>> URL:
>> Submission from: (NULL) (129.215.149.98)
>>
>>
>> In a MMR setup of >=3 servers (4 in this case) you can cause a segfault
>> if you issue the same modification to 2 separate servers within your
>> replication interval.
>> It seems like it's the last server to receive the change falls over when
>> it receives the change from one of the other servers during replication:
> 
> Hi Mark,
> 
> I'm pretty sure you're reporting ITS#8843.  I suggest applying this patch:
> 
> <https://www.openldap.org/devel/gitweb.cgi?p=openldap.git;a=commit;h=cc24cf620470e600d31fd68f63decae82b9745f3>
> 
> 
> --Quanah
> 
> 
> 
> -- 
> 
> Quanah Gibson-Mount
> Product Architect
> Symas Corporation
> Packaged, certified, and supported LDAP solutions powered by OpenLDAP:
> <http://www.symas.com>
> 
> 

-- 
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Mark Cairney
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