enterprise-support team mailing list archive

[PierreF <pierre-fersing@xxxxxxxxxxx>]

Public bug reported:

We have setup a LDAP master-master replication using delta-sync. On the
2-node cluster, one server fail to restart with a segfault immediately
after the startup.

Every time we restart the server, it fail with:

/# slapd -u openldap -g openldap -d stats -f /etc/ldap/slapd.conf 
5315e2a1 @(#) $OpenLDAP: slapd  (Sep 19 2013 22:39:38) $
        buildd@panlong:/build/buildd/openldap-2.4.28/debian/build/servers/slapd
5315e2a1 hdb_db_open: database "cn=accesslog": unclean shutdown detected; attempting recovery.
5315e2a3 hdb_db_open: database "dc=qa,dc=example,dc=net": unclean shutdown detected; attempting recovery.
5315e2a6 <= bdb_inequality_candidates: (entryCSN) not indexed
5315e2db slapd starting
Segmentation fault (core dumped)

On syslog:

slapd[4506]: segfault at 5e ip 00007f13dd954f29 sp 00007f13c0a4c800
error 4 in slapd[7f13dd8bb000+128000]

Using a coredump and slapd-dbg, the stacktrace of segfault is:

#0  syncrepl_op_modify (op=0x7f13c0a4d280, rs=<optimized out>) at ../../../../servers/slapd/syncrepl.c:2132
#1  0x00007f13dd9640fa in overlay_op_walk (op=0x7f13c0a4d280, rs=0x7f13c0a4cd50, which=op_modify, oi=0x7f13de46e2f0, on=<optimized out>) at ../../../../servers/slapd/backover.c:661
#2  0x00007f13dd9642bb in over_op_func (op=0x7f13c0a4d280, rs=<optimized out>, which=<optimized out>) at ../../../../servers/slapd/backover.c:723
#3  0x00007f13dd956b6f in syncrepl_message_to_op (si=0x7f13de46f390, op=0x7f13c0a4d280, msg=0x7f13a8109660) at ../../../../servers/slapd/syncrepl.c:2316
#4  0x00007f13dd95b6ad in do_syncrep2 (si=0x7f13de46f390, op=0x7f13c0a4d280) at ../../../../servers/slapd/syncrepl.c:986
#5  do_syncrepl (ctx=<optimized out>, arg=0x7f13de46f180) at ../../../../servers/slapd/syncrepl.c:1522
#6  0x00007f13dd4559aa in ?? () from /usr/lib/x86_64-linux-gnu/libldap_r-2.4.so.2
#7  0x00007f13dc38de9a in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#8  0x00007f13dc0ba3fd in clone () from /lib/x86_64-linux-gnu/libc.so.6
#9  0x0000000000000000 in ?? ()

This bug look really like upstream bug ITS#7354 [1] :
* failure at same function, at same line (same "if ( ml->sml_flags == SLAP_MOD_INTERNAL )")
* same wrong value in "ml" variable (0x40)
* same setup as title in ITS ticket (delta-syncrepl with master-master)

I don't know how to reproduce the situation, so it's pretty hard to do
test. The fix for this issue is very short, it's a one line fix [2].

Note: If the one-line fix is not backported, another solution could be
to update openldap version to 2.4.33, which include this fix. Sadly
trusty only have 2.4.31.


[1]: http://www.openldap.org/its/index.cgi/Software%20Bugs?id=7354;selectid=7354;usearchives=1
[2]: http://www.openldap.org/devel/gitweb.cgi?p=openldap.git;a=commitdiff;h=3f71f756013a61b6a3cf7c529e1ec42675f5e040

** Affects: openldap (Ubuntu)
     Importance: Undecided
         Status: New

-- 
You received this bug notification because you are a member of Ubuntu
Server/Client Support Team, which is subscribed to openldap in Ubuntu.
Matching subscriptions: Ubuntu Server/Client Support Team
https://bugs.launchpad.net/bugs/1287730

Title:
  openldap segfault on startup with delta-syncrepl MMR

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/openldap/+bug/1287730/+subscriptions