Deadlock when deleting user

[389-ds-bot]

Cloned from Pagure issue: https://pagure.io/389-ds-base/issue/49219

• Created at 2017-04-14 15:16:00 by zeduke
• Closed at 2017-05-12 09:03:08 as invalid
• Assigned to tbordaz (@tbordaz)

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Issue Description

When deleting a user, deadlock occures "sometimes". Only a restart of dirsrv resolve the problem.
I say "sometimes" because it is not then only condition of the bug : most delete operations are successful.

Package Version and Platform

Centos 7.3
389-ds-base-libs-1.3.5.10-18.el7_3.x86_64
389-ds-base-snmp-1.3.5.10-18.el7_3.x86_64
389-ds-base-debuginfo-1.3.5.10-18.el7_3.x86_64
389-ds-base-1.3.5.10-18.el7_3.x86_64

Steps to reproduce

I haven't achieved a deterministic way to reproduce this bug. I have only determined what is the minimal context of the bug. I miss a element I think. So someone can considers that necessary but not sufficient conditions

1. Delete a user : the operation can be time expensive because of memberOf Plugin and Managed Entry plugin
2. Some LDAP ABANDON of LDAP search.
3. SASL/GSSAPI connection of a replica : that is the last access log before deadlock

One time it occurs when adding a user

Actual results

deadlock when deleting user

Expected results

no deadlock when deleting occurs

[389-ds-bot]

Comment from tbordaz (@tbordaz) at 2017-04-14 15:40:20

In this ticket, likely the deadlock is between Threads 30 and 21 that are taking locks (DB and schema-compat map) in opposite order. (Need db lock dump and dumped core of DS)

We know it exists such scenario of deadlocks and are working on a fix.
But I think your IPA configuration is not valid.
You should have:

schema-compat-ignore-subtree: cn=dna,cn=ipa,cn=etc,<main_suffix>
schema-compat-restrict-subtree: <main_suffix>
schema-compat-restrict-subtree: cn=Schema Compatibility,cn=plugins,cn=config

For the following entries:

dn: cn=computers,cn=Schema Compatibility,cn=plugins,cn=config
dn: cn=groups,cn=Schema Compatibility,cn=plugins,cn=config
dn: cn=ng,cn=Schema Compatibility,cn=plugins,cn=config
dn: cn=sudoers,cn=Schema Compatibility,cn=plugins,cn=configdn: cn=users,cn=Schema Compatibility,cn=plugins,cn=config
dn: cn=users,cn=Schema Compatibility,cn=plugins,cn=config

IMHO this ticket should rather be on IPA than DS because configuration of schema-compat is done in IPA.

In conclusion:

• if the deadlock occurs again and you have support case, please get a core dump of DS, also a dump of DB lock (db-stat -CA -N /var/lib/dirsrv/slapd-/db, and usual data (dse.ldif and DS access/errors)
• Try the proposed Schema-compat configuration if it improves the situations
• What version DS/IPA are you using ?

[389-ds-bot]

Comment from tbordaz (@tbordaz) at 2017-04-14 15:40:24

Metadata Update from @tbordaz:

• Custom field type adjusted to defect

[389-ds-bot]

Comment from tbordaz (@tbordaz) at 2017-04-24 09:57:09

Metadata Update from @tbordaz:

• Issue assigned to tbordaz

[389-ds-bot]

Comment from tbordaz (@tbordaz) at 2017-05-12 08:58:41

This bug is a slapi-nis bug. I opened https://pagure.io/slapi-nis/issue/14 to track it and closing this one

[389-ds-bot]

Comment from tbordaz (@tbordaz) at 2017-05-12 09:03:15

Metadata Update from @tbordaz:

• Issue close_status updated to: invalid
• Issue status updated to: Closed (was: Open)