memcached crash bucket_engine.c:1530 : bucket_tap_notify

Thread 1 (Thread 28297):
#0 0x00000000000001d0 in ?? ()
#1 0x00007fa0d39463af in std::map<void const*, Item*, std::less<void const*>, std::allocator<std::pair<void const* const, Item*> > >::key_comp (this=0x7)
at /usr/include/c++/4.3/bits/stl_map.h:591
#2 0x00007fa0d394a0fc in std::__uninitialized_fill_n<true>::uninitialized_fill_n<HistogramBin<unsigned long>*, unsigned long, HistogramBin<unsigned long>>
(__first=0x7fa0d394a0fc, __n=140328733061888, __x=@0x7)
at /usr/include/c++/4.3/bits/stl_uninitialized.h:208
#3 0x00007fa0d649d757 in bucket_tap_notify (handle=0x7fa0d66a21a0,
cookie=0x7fa0c03e7df8, engine_specific=0x0, nengine=0, ttl=0 '\000',
tap_flags=7, tap_event=TAP_ACK, tap_seqno=54035, key=0x7fa0c17cbd28,
nkey=0, flags=0, exptime=0, cas=0, data=0x0, ndata=0, vbucket=0)
at bucket_engine.c:1530
#4 0x00000000004045a0 in process_bin_tap_ack (c=0x7fa0c03e7df8)
at daemon/memcached.c:2743
#5 0x000000000040e72a in complete_nread_binary (c=0xfa6c1c0)
at daemon/memcached.c:3381
#6 0x000000000040f958 in complete_nread (c=0x7fa0c03e7df8)
at daemon/memcached.c:3471
#7 conn_nread (c=0x7fa0c03e7df8) at daemon/memcached.c:5275
#8 0x000000000040724b in event_handler (fd=<value optimized out>,
which=<value optimized out>, arg=0x7fa0c03e7df8)
at daemon/memcached.c:5576
#9 0x00007fa0d84e73cd in event_process_active_single_queue (base=0x23084a0,
flags=<value optimized out>) at event.c:1308
#10 event_process_active (base=0x23084a0, flags=<value optimized out>)
at event.c:1375
#11 event_base_loop (base=0x23084a0, flags=<value optimized out>)
at event.c:1572
#12 0x0000000000414824 in worker_libevent (arg=0x2305fc0)
at daemon/thread.c:304
#13 0x00007fa0d7c2f9ca in start_thread () from /lib/libpthread.so.0
#14 0x00007fa0d798d6cd in clone () from /lib/libc.so.6
#15 0x0000000000000000 in ?? ()