I've got the same crash during mmrepl/fractional test execution.

Sankar, do you happen to keep all the error and access logs from the crashed tet run?

The crash is in this disconnect error case.  I wonder what happened on the other side.  Thanks.
452                    if (IS_DISCONNECT_ERROR(rc))
453                    {
454                        close_connection_internal(conn); /* we already have the lock */
455                        return_value = CONN_NOT_CONNECTED;
456                    }

Also, result files mmraccept.*.out.* are available?

I assume the core file core.11123 is from slapd-s1.  Is that correct?

I've repeated mmr/accept iclist="ic0 ic1 ic2 ic3 ic4" 3 times on a beaker box: tyan-gt24-13.rhts.eng.bos.redhat.com.  So far, no luck.  Might it need beefier machine?  Could it be possible to let me login the test machine which got the crash?

(In reply to Noriko Hosoi from comment #6)
> I've repeated mmr/accept iclist="ic0 ic1 ic2 ic3 ic4" 3 times on a beaker
> box: tyan-gt24-13.rhts.eng.bos.redhat.com.  So far, no luck.  Might it need
> beefier machine?  Could it be possible to let me login the test machine
Sure!
Host - cloud-qe-4.idmqe.lab.eng.bos.redhat.com
Creds - root/Default beaker root passwd.
> which got the crash?

(In reply to Noriko Hosoi from comment #5)
> Also, result files mmraccept.*.out.* are available?
> 
> I assume the core file core.11123 is from slapd-s1.  Is that correct?

That is true. The instance slap-s1 has crashed. I kept the core files backed up in /export on cloud-qe-4.idmqe.lab.eng.bos.redhat.com.

Thank you, Sankar.

I think the server should not crash, but the priority of this case may be low.

trac47606 modifies the maxbersize of C1 to check the error handling.  It's supposed to set back to the original like this in mmr/accept/accept.sh:
5730     message "C1: Setting nsslapd-maxbersize: $MAXBERSIZE"
5731     $LDAPMODIFY -p $C1PORT -h localhost -D "${REPLINSTROOTDN}" -w ${REPLINSTROOTPW} <<EOF
5732 dn: cn=config
5733 changetype: modify
5734 replace: nsslapd-maxbersize
5735 nsslapd-maxbersize: $MAXBERSIZE
5736 EOF

But somehow, it failed like this (cloud-qe-4.idmqe.lab.eng.bos.redhat.com:/tet/testcases/DS/6.0/tet_tmp_dir/32090/mmraccept.run.out):
S1->C1: Adding an entry > 2MB is supposed to be logged in C1 error log

C1: Incoming BER Element size is 
expr: syntax error
C1: Setting nsslapd-maxbersize: 
ldap_modify: Invalid syntax
ldap_modify: additional info: nsslapd-maxbersize: value #0 invalid per syntax

Due to the too low maxbersize on C1:
# egrep maxbersize /etc/dirsrv/slapd-c1/dse.ldif
nsslapd-maxbersize: 20480
some of the following {s1,s2}->c1 replications failed, e.g.:
[29/Oct/2015:15:21:50 -0400] connection - conn=95963 fd=64 Incoming BER Element was 220429 bytes, max allowable is 20480 bytes. Change the nsslapd-maxbersize attribute in cn=config to increase.

This is a sample error on S1->C1, in which schema replication failed.  Please note that "Can't contact LDAP server" is returned when the maxbersize is too small.  So, I would think this is one of the failure cases I described.  Also, at this point 15:21:40, we could guarantee C1 is up from the log.
[29/Oct/2015:15:21:39 -0400] NSMMReplicationPlugin - agmt="cn=24202_to_24206" (cloud-qe-4:24206): Replication bind with SIMPLE auth resumed
[29/Oct/2015:15:21:40 -0400] NSMMReplicationPlugin - agmt="cn=24202_to_24206" (cloud-qe-4:24206): Warning: unable to replicate schema: rc=2
[29/Oct/2015:15:21:40 -0400] NSMMReplicationPlugin - agmt="cn=24202_to_24206" (cloud-qe-4:24206): Failed to send update operation to consumer 
(uniqueid b39b3cb4-7c9311e5-90c5ba22-3d0bc543, CSN 562f4f05000000010000): Can't contact LDAP server. Will retry later.
[29/Oct/2015:15:21:40 -0400] NSMMReplicationPlugin - agmt="cn=24202_to_24206" (cloud-qe-4:24206): Consumer failed to replay change (uniqueid (
null), CSN (null)): Can't contact LDAP server(-1). Will retry later.
[29/Oct/2015:15:21:40 -0400] NSMMReplicationPlugin - agmt="cn=24202_to_24206" (cloud-qe-4:24206): Warning: unable to send endReplication exten
ded operation (Can't contact LDAP server)

Could you please fix the trac47606 test case to make sure it sets back the original (or default) maxbersize and rerun the test?  If it eliminates the crash, I'm going to push it to 7.3.  Thanks.

Modified the trac47606 tests to reset the value for nsslapd-maxbersize after test execution and restarted the same set of tests to check if there is a crash. 
$LDAPMODIFY -p $C1PORT -h localhost -D "${REPLINSTROOTDN}" -w ${REPLINSTROOTPW} <<EOF
dn: cn=config
changetype: modify
replace: nsslapd-maxbersize
nsslapd-maxbersize: 10485760
EOF

With this, the execution just went fine. No crash.
http://wiki.idm.lab.bos.redhat.com/qa/archive/beaker/x86_64/389-ds-base-1.3.4.0-19/Linux/20151101-022701.html

Good news.  Thanks for the result, Sankar.

Pushing the target to 7.3.