segmentation fault at #0 HashTable::set(

[root@localhost backup]# gdb /opt/couchbase/bin/memcached core.memcached.30169
GNU gdb (GDB) CentOS (7.0.1-42.el5.centos)
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /opt/couchbase/bin/memcached...done.
[New Thread 30174]
[New Thread 30938]
[New Thread 30937]
[New Thread 30936]
[New Thread 30935]
[New Thread 30176]
[New Thread 30175]
[New Thread 30173]
[New Thread 30172]
[New Thread 30171]
[New Thread 30170]
[New Thread 30169]
Reading symbols from /opt/couchbase/lib/memcached/libmemcached_utilities.so.0...done.
Loaded symbols for /opt/couchbase/lib/memcached/libmemcached_utilities.so.0
Reading symbols from /opt/couchbase/lib/libevent-2.0.so.5...done.
Loaded symbols for /opt/couchbase/lib/libevent-2.0.so.5
Reading symbols from /lib64/libdl.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/libdl.so.2
Reading symbols from /lib64/libm.so.6...(no debugging symbols found)...done.
Loaded symbols for /lib64/libm.so.6
Reading symbols from /lib64/librt.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib64/librt.so.1
Reading symbols from /opt/couchbase/lib/libtcmalloc_minimal.so.4...done.
Loaded symbols for /opt/couchbase/lib/libtcmalloc_minimal.so.4
Reading symbols from /lib64/libpthread.so.0...(no debugging symbols found)...done.
[Thread debugging using libthread_db enabled]
Loaded symbols for /lib64/libpthread.so.0
Reading symbols from /lib64/libc.so.6...(no debugging symbols found)...done.
Loaded symbols for /lib64/libc.so.6
Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Reading symbols from /usr/lib64/libstdc++.so.6...(no debugging symbols found)...done.
Loaded symbols for /usr/lib64/libstdc++.so.6
Reading symbols from /lib64/libgcc_s.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib64/libgcc_s.so.1
Reading symbols from /opt/couchbase/lib/memcached/stdin_term_handler.so...done.
Loaded symbols for /opt/couchbase/lib/memcached/stdin_term_handler.so
Reading symbols from /opt/couchbase/lib/memcached/bucket_engine.so...done.
Loaded symbols for /opt/couchbase/lib/memcached/bucket_engine.so
Reading symbols from /opt/couchbase/lib/memcached/ep.so...done.
Loaded symbols for /opt/couchbase/lib/memcached/ep.so
Reading symbols from /opt/couchbase/lib/libcouchstore.so.1...done.
Loaded symbols for /opt/couchbase/lib/libcouchstore.so.1
Reading symbols from /opt/couchbase/lib/libsnappy.so.1...done.
Loaded symbols for /opt/couchbase/lib/libsnappy.so.1
Reading symbols from /lib64/libnss_files.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/libnss_files.so.2

warning: no loadable sections found in added symbol-file system-supplied DSO at 0x7fff83dfd000
Core was generated by `/opt/couchbase/bin/memcached -X /opt/couchbase/lib/memcached/stdin_term_handler'.
Program terminated with signal 11, Segmentation fault.
#0 0x00002aaaaad44909 in HashTable::set(Item const&, unsigned long, long&, bool, bool) ()
from /opt/couchbase/lib/memcached/ep.so
(gdb) t a a bt

Thread 12 (Thread 0x2ad7033be240 (LWP 30169)):
#0 0x00002ad702c2a8a8 in epoll_wait () from /lib64/libc.so.6
#1 0x00002ad701e39c28 in epoll_dispatch (base=0x1dea0000, tv=<value optimized out>) at epoll.c:404
#2 0x00002ad701e28a4c in event_base_loop (base=0x1dea0000, flags=0) at event.c:1558
#3 0x00000000004092f6 in main (argc=<value optimized out>, argv=<value optimized out>) at daemon/memcached.c:7794

Thread 11 (Thread 30170):
#0 0x00002ad702c1c78b in read () from /lib64/libc.so.6
#1 0x00002ad702bc2d57 in _IO_new_file_underflow () from /lib64/libc.so.6
#2 0x00002ad702bc371e in _IO_default_uflow_internal () from /lib64/libc.so.6
#3 0x00002ad702bbefdb in getc () from /lib64/libc.so.6
#4 0x00002ad7033bf879 in check_stdin_thread (arg=0x4033f0) at extensions/daemon/stdin_check.c:19
#5 0x00002ad70294173d in start_thread () from /lib64/libpthread.so.0
#6 0x00002ad702c2a4bd in clone () from /lib64/libc.so.6

Thread 10 (Thread 30171):
#0 0x00002ad702bf0541 in nanosleep () from /lib64/libc.so.6
#1 0x00002ad702bf0364 in sleep () from /lib64/libc.so.6
#2 0x00000000004157b8 in check_isasl_db_thread (arg=<value optimized out>) at daemon/isasl.c:233
#3 0x00002ad70294173d in start_thread () from /lib64/libpthread.so.0
#4 0x00002ad702c2a4bd in clone () from /lib64/libc.so.6

Thread 9 (Thread 30172):
#0 0x00002ad702c2a8a8 in epoll_wait () from /lib64/libc.so.6
#1 0x00002ad701e39c28 in epoll_dispatch (base=0x1dea0500, tv=<value optimized out>) at epoll.c:404
#2 0x00002ad701e28a4c in event_base_loop (base=0x1dea0500, flags=0) at event.c:1558
#3 0x0000000000413b54 in worker_libevent (arg=<value optimized out>) at daemon/thread.c:304
#4 0x00002ad70294173d in start_thread () from /lib64/libpthread.so.0
#5 0x00002ad702c2a4bd in clone () from /lib64/libc.so.6

--Type <return> to continue, or q <return> to quit--
Thread 8 (Thread 30173):
#0 0x00002ad702c2a8a8 in epoll_wait () from /lib64/libc.so.6
#1 0x00002ad701e39c28 in epoll_dispatch (base=0x1dea0280, tv=<value optimized out>) at epoll.c:404
#2 0x00002ad701e28a4c in event_base_loop (base=0x1dea0280, flags=0) at event.c:1558
#3 0x0000000000413b54 in worker_libevent (arg=<value optimized out>) at daemon/thread.c:304
#4 0x00002ad70294173d in start_thread () from /lib64/libpthread.so.0
#5 0x00002ad702c2a4bd in clone () from /lib64/libc.so.6

Thread 7 (Thread 30175):
#0 0x00002ad702c2a8a8 in epoll_wait () from /lib64/libc.so.6
#1 0x00002ad701e39c28 in epoll_dispatch (base=0x1dea0a00, tv=<value optimized out>) at epoll.c:404
#2 0x00002ad701e28a4c in event_base_loop (base=0x1dea0a00, flags=0) at event.c:1558
#3 0x0000000000413b54 in worker_libevent (arg=<value optimized out>) at daemon/thread.c:304
#4 0x00002ad70294173d in start_thread () from /lib64/libpthread.so.0
#5 0x00002ad702c2a4bd in clone () from /lib64/libc.so.6

Thread 6 (Thread 30176):
#0 0x00002ad702c2a8a8 in epoll_wait () from /lib64/libc.so.6
#1 0x00002ad701e39c28 in epoll_dispatch (base=0x1dea0780, tv=<value optimized out>) at epoll.c:404
#2 0x00002ad701e28a4c in event_base_loop (base=0x1dea0780, flags=0) at event.c:1558
#3 0x0000000000413b54 in worker_libevent (arg=<value optimized out>) at daemon/thread.c:304
#4 0x00002ad70294173d in start_thread () from /lib64/libpthread.so.0
#5 0x00002ad702c2a4bd in clone () from /lib64/libc.so.6

Thread 5 (Thread 30935):
#0 0x00002ad702945ee9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x00002aaaaad2ce47 in wait (this=0x1df49340) at syncobject.hh:36
#2 Dispatcher::run (this=0x1df49340) at dispatcher.cc:89
#3 0x00002aaaaad2d47b in launch_dispatcher_thread (arg=<value optimized out>) at dispatcher.cc:28
#4 0x00002ad70294173d in start_thread () from /lib64/libpthread.so.0
#5 0x00002ad702c2a4bd in clone () from /lib64/libc.so.6
--Type <return> to continue, or q <return> to quit--

Thread 4 (Thread 30936):
#0 0x00002ad7029490a7 in fsync () from /lib64/libpthread.so.0
#1 0x00002aaaab0cc517 in couch_sync (db=<value optimized out>) at src/os.c:91
#2 0x00002aaaaadc5e87 in CouchKVStore::saveDocs (this=0x1df6c090, vbid=84, rev=1, docs=0x2305daa0,
docinfos=0x1ea69aa0, docCount=61) at couch-kvstore/couch-kvstore.cc:1126
#3 0x00002aaaaadc6418 in CouchKVStore::commit2couchstore (this=0x1df6c090) at couch-kvstore/couch-kvstore.cc:1028
#4 0x00002aaaaadc660f in CouchKVStore::commit (this=0x1df6c090) at couch-kvstore/couch-kvstore.cc:588
#5 0x00002aaaaad3a1b2 in TransactionContext::commit (this=0x1dff48e0) at ep.cc:2669
#6 0x00002aaaaad3a72d in EventuallyPersistentStore::flushSome (this=0x1dff4580, q=0x1dff4840,
rejectQueue=0x22ea2780) at ep.cc:1974
#7 0x00002aaaaad64604 in Flusher::doFlush (this=0x1df6c000) at flusher.cc:244
#8 0x00002aaaaad651d5 in Flusher::step (this=0x1df6c000, d=..., tid=std::tr1::shared_ptr (count 5) 0x1df66180)
at flusher.cc:158
#9 0x00002aaaaad65850 in FlusherStepper::callback (this=<value optimized out>, d=<value optimized out>,
t=<value optimized out>) at flusher.cc:23
#10 0x00002aaaaad2dd3f in Task::run(Dispatcher&, std::tr1::shared_ptr<Task>) ()
from /opt/couchbase/lib/memcached/ep.so
#11 0x00002aaaaad2cbf0 in Dispatcher::run (this=0x1df496c0) at dispatcher.cc:123
#12 0x00002aaaaad2d47b in launch_dispatcher_thread (arg=<value optimized out>) at dispatcher.cc:28
#13 0x00002ad70294173d in start_thread () from /lib64/libpthread.so.0
#14 0x00002ad702c2a4bd in clone () from /lib64/libc.so.6

Thread 3 (Thread 30937):
#0 0x00002ad702946150 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x00002aaaaad2a600 in wait (this=0x1df66500, d=...) at syncobject.hh:47
#2 IdleTask::run (this=0x1df66500, d=...) at dispatcher.cc:294
#3 0x00002aaaaad2cbf0 in Dispatcher::run (this=0x1df48000) at dispatcher.cc:123
#4 0x00002aaaaad2d47b in launch_dispatcher_thread (arg=<value optimized out>) at dispatcher.cc:28
#5 0x00002ad70294173d in start_thread () from /lib64/libpthread.so.0
#6 0x00002ad702c2a4bd in clone () from /lib64/libc.so.6
--Type <return> to continue, or q <return> to quit--

Thread 2 (Thread 30938):
#0 0x00002ad702946150 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x00002aaaaad4a36d in wait (this=0x1fe59600) at syncobject.hh:47
#2 wait (this=0x1fe59600) at syncobject.hh:63
#3 wait (this=0x1fe59600) at tapconnmap.hh:203
#4 EventuallyPersistentEngine::notifyPendingConnections (this=0x1fe59600) at ep_engine.cc:3302
#5 0x00002aaaaad4a461 in EvpNotifyPendingConns (arg=0x1fe59600) at ep_engine.cc:1015
#6 0x00002ad70294173d in start_thread () from /lib64/libpthread.so.0
#7 0x00002ad702c2a4bd in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x439ee940 (LWP 30174)):
#0 0x00002aaaaad44909 in HashTable::set(Item const&, unsigned long, long&, bool, bool) ()
from /opt/couchbase/lib/memcached/ep.so
#1 0x00002aaaaad360ff in set (this=0x1dff4580, itm=..., cookie=0x1de47600, force=<value optimized out>)
at stored-value.hh:1073
#2 EventuallyPersistentStore::set (this=0x1dff4580, itm=..., cookie=0x1de47600, force=<value optimized out>)
at ep.cc:868
#3 0x00002aaaaad58699 in EventuallyPersistentEngine::store (this=0x1fe59600, cookie=0x1de47600, itm=0x1e6060c0,
cas=0x1de47858, operation=<value optimized out>, vbucket=<value optimized out>) at ep_engine.cc:1366
#4 0x00002aaaaaab125c in bucket_store (handle=<value optimized out>, cookie=0x1de47600, itm=0x1e6060c0,
cas=0x1de47858, operation=OPERATION_SET, vbucket=<value optimized out>) at bucket_engine.c:1741
#5 0x000000000040d351 in complete_update_bin (c=0x1de47600) at daemon/memcached.c:1795
#6 0x000000000040ff8d in complete_nread_binary (c=0x1de47600) at daemon/memcached.c:3638
#7 complete_nread (c=0x1de47600) at daemon/memcached.c:3756
#8 conn_nread (c=0x1de47600) at daemon/memcached.c:5580
#9 0x00000000004070fc in event_handler (fd=<value optimized out>, which=<value optimized out>, arg=0x1de47600)
at daemon/memcached.c:5881
#10 0x00002ad701e28df9 in event_process_active_single_queue (base=0x1dea0c80, flags=0) at event.c:1308
#11 event_process_active (base=0x1dea0c80, flags=0) at event.c:1375
#12 event_base_loop (base=0x1dea0c80, flags=0) at event.c:1572