[FTS] crash happens occasionally while system is idle

Logs : https://s3.amazonaws.com/cb-customers/cbft/99/collectinfo-2016-05-03T184739-ns_1%40127.0.0.1.zip

[IP] 172.23.123.38 /root/couchbase

Lot of .dmp files

Couchbase: version : 4.5.2442

Error log:
Service 'fts' exited with status 1. Restarting. Messages: }
[FDB ERR] Error in reading the doc length metadata with offset 164456302 from a database file '/opt/couchbase/var/lib/couchbase/data/@fts/perf_fts_index_a9d1c5ed4abf5fc6_0a44bddb.pindex/store.0'
2016-05-03T15:22:13.102-07:00 [INFO] cbdatasource: server: 127.0.0.1:11210, uprOpenName: fts:perf_fts_index_a9d1c5ed4abf5fc6-65a33df, worker, looping beg, vbucketState: "running" (has 1024 vbuckets), 0-1023
2016-05-03T15:22:43.103-07:00 [INFO] cbdatasource: server: 127.0.0.1:11210, uprOpenName: fts:perf_fts_index_a9d1c5ed4abf5fc6-65a33df, worker, looping beg, vbucketState: "running" (has 1024 vbuckets), 0-1023
[goport] 2016/05/03 15:23:04 /opt/couchbase/bin/cbft terminated: signal: segmentation fault (core dumped) ns_log 000 ns_1@127.0.0.1 3:23:04 PM Tue May 3, 2016
Service 'fts' exited with status 1. Restarting. Messages: "total_gc": 3065
}

[goport] 2016/05/02 23:20:17 /opt/couchbase/bin/cbft terminated: signal: segmentation fault (core dumped)

Scenario:

The system was completely idle. Only couchbase is up and running . CBFT was running , one index was created. The system was completely without load . Occasionally it crashes .

How to Repro:
I have no way to repro this . I have seen this crash many times on my system.