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DB2 instance crash in LDAP libraries

Troubleshooting


Problem

DB2 trap files created when the LDAP libraries crash unexpectedly.

Symptom

Sample stack in DB2 trap files

The trap file shows the crash is caused by LDAP library: libnss_ldap.so.2


-----FUNC-ADDR---- ------FUNCTION + OFFSET------
0x00002B5EFE1A4959 ossDumpStackTraceEx + 0x0201
(/opt/ibm/db2/V9.5/lib64/libdb2osse.so.1)
0x00002B5EFE1A045A _ZN11OSSTrapFile6dumpExEmiP7siginfoPvm + 0x00b4
(/opt/ibm/db2/V9.5/lib64/libdb2osse.so.1)
0x00002B5EFE1A0521 _ZN11OSSTrapFile4dumpEmiP7siginfoPv + 0x0009 (/opt/ibm/db2/V9.5/lib64/libdb2osse.so.1)
0x00002B5EFA484C02 sqlo_trce + 0x050e (/opt/ibm/db2/V9.5/lib64/libdb2e.so.1)
0x00002B5EFA4C8BFE sqloEDUCodeTrapHandler + 0x024c (/opt/ibm/db2/V9.5/lib64/libdb2e.so.1)
0x00002B5EF7B1DB10 address: 0x00002B5EF7B1DB10 ; dladdress:
0x00002B5EF7B0F000 ; offset in lib: 0x000000000000EB10 ; (/lib64/libpthread.so.0)
0x00002B5EFED98265 gsignal + 0x0035 (/lib64/libc.so.6)
0x00002B5EFED99D10 abort + 0x0110 (/lib64/libc.so.6)
0x00002B5EFED916E6 __assert_fail + 0x00f6 (/lib64/libc.so.6)
0x00002B5F177C5335 address: 0x00002B5F177C5335 ; dladdress:
0x00002B5F1776F000 ; offset in lib: 0x0000000000056335 ; (/lib64/libnss_ldap.so.2)
0x00002B5F177B8645 address: 0x00002B5F177B8645 ; dladdress:
0x00002B5F1776F000 ; offset in lib: 0x0000000000049645 ; (/lib64/libnss_ldap.so.2)
0x00002B5F177B99CF _nss_ldap_ent_context_release + 0x002f (/lib64/libnss_ldap.so.2)
0x00002B5F177BBD8A _nss_ldap_initgroups_dyn + 0x01da (/lib64/libnss_ldap.so.2)
0x00002B5EFEDFF531 address: 0x00002B5EFEDFF531 ; dladdress:
0x00002B5EFED68000 ; offset in lib: 0x0000000000097531 ; (/lib64/libc.so.6)
0x00002B5EFEDFF7DA getgrouplist + 0x006a (/lib64/libc.so.6)
0x00002B5EFA4A5882 sqlogetgroupsforuser + 0x01a8 (/opt/ibm/db2/V9.5/lib64/libdb2e.so.1)
0x00002B5EF8F53CDA _Z12secGetGroupsPcPvPKciPS_PiS2_ii + 0x06d2
(/opt/ibm/db2/V9.5/lib64/libdb2e.so.1)
0x00002B5F1722D7E0 _Z19osplugin_get_groupsPcPvPKciPS_PiS2_ii + 0x006e
(/home/db2p/sqllib/security64/plugin/IBM/group/IBMOSgroups.so)
0x00002B5F1722D378

Cause

DB2 depends on operating system for user authentication and group enumeration.
DB2 does not support direct LDAP authentication and group enumeration through operating system.
There are known issues with unexpected crash or hang.

Operating system: /etc/nsswitch.out shows if the operating system has been configured to use LDAP for authentication.

For example:

    passwd:         files ldap 
    group:          files ldap
    shadow:         files ldap

Resolving The Problem

The resolution is to configure either DB2 LDAP security plugin or Transparent LDAP with DB2 in order to use LDAP authentication.

The supported method to use DB2 with LDAP authentication is through LDAP security plugin or Transparent LDAP configuration.
The set up steps are in the URL below:
http://publib.boulder.ibm.com/infocenter/db2luw/v9r5/topic/com.ibm.db2.luw.admin.sec.doc/doc/c0050519.html

[{"Product":{"code":"SSEPGG","label":"Db2 for Linux, UNIX and Windows"},"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Component":"Security \/ Plug-Ins - LDAP","Platform":[{"code":"PF002","label":"AIX"},{"code":"PF010","label":"HP-UX"},{"code":"PF016","label":"Linux"},{"code":"PF027","label":"Solaris"}],"Version":"9.7;9.5;9.1","Edition":"Advanced Enterprise Server;Enterprise Server;Workgroup Server","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
16 June 2018

UID

swg21473165

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