deleting database directory makes ep-engine 'hang' in TransactionContext::commit

I've abruptly stopped service and did make dataclean which deleted data directory. But I'm seeing memcacheds being stuck. Here's backtrace:

oaded symbols for /lib/libgcc_s.so.1
0xffffe430 in __kernel_vsyscall ()
(gdb) thread apply all bt

Thread 5 (Thread 0xf6ca5b70 (LWP 21388)):
#0 0xffffe430 in __kernel_vsyscall ()
#1 0xf75a03f6 in nanosleep () at ../sysdeps/unix/syscall-template.S:82
#2 0xf75a0220 in __sleep (seconds=0) at ../sysdeps/unix/sysv/linux/sleep.c:138
#3 0x08062317 in check_isasl_db_thread (arg=0x806afd4) at daemon/isasl.c:220
#4 0xf76b8c39 in start_thread (arg=0xf6ca5b70) at pthread_create.c:304
#5 0xf75d591e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

Thread 4 (Thread 0xf381db70 (LWP 21400)):
#0 0xffffe430 in __kernel_vsyscall ()
#1 0xf76bd20a in __pthread_cond_wait (cond=0x97fcce8, mutex=0x97fcccc) at pthread_cond_wait.c:153
#2 0xf39a70d0 in SyncObject::wait (this=0x97fccc8) at syncobject.hh:31
#3 0xf39a5ce3 in Dispatcher::run (this=0x97fccc0) at dispatcher.cc:85
#4 0xf39a5853 in launch_dispatcher_thread (arg=0x97fccc0) at dispatcher.cc:28
#5 0xf76b8c39 in start_thread (arg=0xf381db70) at pthread_create.c:304
#6 0xf75d591e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

Thread 3 (Thread 0xf301cb70 (LWP 21401)):
#0 0xffffe430 in __kernel_vsyscall ()
#1 0xf75a03f6 in nanosleep () at ../sysdeps/unix/syscall-template.S:82
#2 0xf75a0220 in __sleep (seconds=0) at ../sysdeps/unix/sysv/linux/sleep.c:138
#3 0xf39b274b in TransactionContext::commit (this=0x8b875e4) at ep.cc:2114
#4 0xf39b01e5 in EventuallyPersistentStore::flushSome (this=0x8b87500, q=0x8b875b0, rejectQueue=0xb2853c0) at ep.cc:1491
#5 0xf39f36da in Flusher::doFlush (this=0xa362810) at flusher.cc:240
#6 0xf39f34dc in Flusher::completeFlush (this=0xa362810) at flusher.cc:202
#7 0xf39f3284 in Flusher::step (this=0xa362810, d=..., tid=std::tr1::shared_ptr (count 5) 0xabfec38) at flusher.cc:174
#8 0xf39f28d1 in FlusherStepper::callback (this=0xac5dbb0, d=..., t=std::tr1::shared_ptr (count 5) 0xabfec38) at flusher.cc:23
#9 0xf39a76fa in Task::run (this=0xabfec38, d=..., t=std::tr1::shared_ptr (count 5) 0xabfec38) at dispatcher.hh:139
#10 0xf39a5f6c in Dispatcher::run (this=0x92b2378) at dispatcher.cc:119
#11 0xf39a5853 in launch_dispatcher_thread (arg=0x92b2378) at dispatcher.cc:28
#12 0xf76b8c39 in start_thread (arg=0xf301cb70) at pthread_create.c:304
#13 0xf75d591e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
--Type <return> to continue, or q <return> to quit--

Thread 2 (Thread 0xf281bb70 (LWP 21402)):
#0 0xffffe430 in __kernel_vsyscall ()
#1 0xf76bd703 in pthread_cond_timedwait@@GLIBC_2.3.2 ()
at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/pthread_cond_timedwait.S:236
#2 0xf39a71de in SyncObject::wait (this=0xa361c60, tv=...) at syncobject.hh:42
#3 0xf39a6d77 in IdleTask::run (this=0xa362798, d=...) at dispatcher.cc:244
#4 0xf39a5f6c in Dispatcher::run (this=0xa361c58) at dispatcher.cc:119
#5 0xf39a5853 in launch_dispatcher_thread (arg=0xa361c58) at dispatcher.cc:28
#6 0xf76b8c39 in start_thread (arg=0xf281bb70) at pthread_create.c:304
#7 0xf75d591e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

Thread 1 (Thread 0xf74dc9a0 (LWP 21384)):
#0 0xffffe430 in __kernel_vsyscall ()
#1 0xf75a03f6 in nanosleep () at ../sysdeps/unix/syscall-template.S:82
#2 0xf75cf61c in usleep (useconds=1000) at ../sysdeps/unix/sysv/linux/usleep.c:33
#3 0xf39f2947 in Flusher::wait (this=0xa362810) at flusher.cc:33
#4 0xf39aa781 in EventuallyPersistentStore::stopFlusher (this=0x8b87500) at ep.cc:447
#5 0xf39aa4aa in EventuallyPersistentStore::~EventuallyPersistentStore (this=0x8b87500, __in_chrg=<value optimized out>)
at ep.cc:414
#6 0xf39dac41 in EventuallyPersistentEngine::~EventuallyPersistentEngine (this=0x8936280, __in_chrg=<value optimized out>)
at ep_engine.h:505
#7 0xf39c6706 in EvpDestroy (handle=0x8936280, force=false) at ep_engine.cc:97
#8 0xf76e3da9 in bucket_shutdown_engine (key=0x893b810, nkey=7, val=0x8905c40, nval=0, args=0x0) at bucket_engine.c:1027
#9 0xf76b0de7 in genhash_iter (h=0x88bd4a8, iterfunc=0xf76e3d3e <bucket_shutdown_engine>, arg=0x0) at utilities/genhash.c:270
#10 0xf76e3e7e in bucket_destroy (handle=0xf76e8220, force=false) at bucket_engine.c:1051
#11 0x0805e1b1 in main (argc=17, argv=0xffa04d74) at daemon/memcached.c:7467
(gdb)
(gdb) thread 3
[Switching to thread 3 (Thread 0xf301cb70 (LWP 21401))]#0 0xffffe430 in __kernel_vsyscall ()
(gdb) fin
Run till exit from #0 0xffffe430 in __kernel_vsyscall ()
0xf75a03f6 in nanosleep () at ../sysdeps/unix/syscall-template.S:82
82 ../sysdeps/unix/syscall-template.S: No such file or directory.
in ../sysdeps/unix/syscall-template.S
(gdb)
Run till exit from #0 0xf75a03f6 in nanosleep () at ../sysdeps/unix/syscall-template.S:82
__sleep (seconds=0) at ../sysdeps/unix/sysv/linux/sleep.c:139
139 ../sysdeps/unix/sysv/linux/sleep.c: No such file or directory.
in ../sysdeps/unix/sysv/linux/sleep.c
(gdb)
Run till exit from #0 __sleep (seconds=0) at ../sysdeps/unix/sysv/linux/sleep.c:139
TransactionContext::commit (this=0x8b875e4) at ep.cc:2115
2115 ++stats.commitFailed;
Value returned is $1 = 0
(gdb) s
Atomic<unsigned int>::operator++ (this=0x893669c) at atomic.hh:130
130 return ep_sync_add_and_fetch(&value, 1);
(gdb) bt
#0 Atomic<unsigned int>::operator++ (this=0x893669c) at atomic.hh:130
#1 0xf39b275b in TransactionContext::commit (this=0x8b875e4) at ep.cc:2115
#2 0xf39b01e5 in EventuallyPersistentStore::flushSome (this=0x8b87500, q=0x8b875b0, rejectQueue=0xb2853c0) at ep.cc:1491
#3 0xf39f36da in Flusher::doFlush (this=0xa362810) at flusher.cc:240
#4 0xf39f34dc in Flusher::completeFlush (this=0xa362810) at flusher.cc:202
#5 0xf39f3284 in Flusher::step (this=0xa362810, d=..., tid=std::tr1::shared_ptr (count 5) 0xabfec38) at flusher.cc:174
#6 0xf39f28d1 in FlusherStepper::callback (this=0xac5dbb0, d=..., t=std::tr1::shared_ptr (count 5) 0xabfec38) at flusher.cc:23
#7 0xf39a76fa in Task::run (this=0xabfec38, d=..., t=std::tr1::shared_ptr (count 5) 0xabfec38) at dispatcher.hh:139
#8 0xf39a5f6c in Dispatcher::run (this=0x92b2378) at dispatcher.cc:119
#9 0xf39a5853 in launch_dispatcher_thread (arg=0x92b2378) at dispatcher.cc:28
#10 0xf76b8c39 in start_thread (arg=0xf301cb70) at pthread_create.c:304
#11 0xf75d591e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
(gdb) fin
Run till exit from #0 Atomic<unsigned int>::operator++ (this=0x893669c) at atomic.hh:130
TransactionContext::commit (this=0x8b875e4) at ep.cc:2113
2113 while (!underlying->commit()) {
Value returned is $2 = 269
(gdb) s
StrategicSqlite3::commit (this=0x893bbf8) at sqlite-kvstore.hh:70
70 if(intransaction)

{ (gdb) n 72 intransaction = (execute("commit") == -1); (gdb) n 75 return !intransaction; (gdb) p intransaction $3 = true (gdb) s 76 }

(gdb)
TransactionContext::commit (this=0x8b875e4) at ep.cc:2114
2114 sleep(1);
(gdb) q
A debugging session is active.

Inferior 1 [process 21384] will be detached.

Quit anyway? (y or n) y