eclccserver does not terminate cleanly

#0  0x00007f6ac82177d0 in ?? ()
#1  0x00007f6ac8913c6b in CCommunicator::sendRecv (this=0x55bc3076c350, mbuff=..., sendrank=0, sendtag=MPTAG_DALI_SDS_REQUEST, timeout=4294967295)
    at /home/gavin/dev/hpcc/system/mp/mpcomm.cpp:3137
#2  0x00007f6ac8a787f3 in CCovenClient::sendRecv (this=0x55bc3076bf10, mbuff=..., sendrank=4294967293, sendtag=MPTAG_DALI_SDS_REQUEST, 
    timeout=4294967295) at /home/gavin/dev/hpcc/dali/base/dacoven.cpp:882
#3  0x00007f6ac8a86c75 in CClientSDSManager::sendRequest (this=0x55bc30777530, mb=..., throttle=false)
    at /home/gavin/dev/hpcc/dali/base/dacsds.cpp:1308
#4  0x00007f6ac8a88a02 in CClientSDSManager::commit (this=0x55bc30777530, connection=..., disconnectDeleteRoot=0x7ffe2e49bed7)
    at /home/gavin/dev/hpcc/dali/base/dacsds.cpp:1596
#5  0x00007f6ac8a91628 in CRemoteConnection::beforeDispose (this=0x55bc307769b0) at /home/gavin/dev/hpcc/dali/base/dacsds.ipp:46
#6  0x00007f6ac8523bf3 in CInterfaceOf<CEmptyClass>::Release (this=0x55bc307769b0) at /home/gavin/dev/hpcc/system/jlib/jiface.hpp:151
#7  0x00007f6ac8523aeb in CInterface::Release (this=0x55bc307769b0) at /home/gavin/dev/hpcc/system/jlib/jiface.cpp:33
#8  0x00007f6ac8a91505 in CRemoteConnection::Release (this=0x55bc307769b0) at /home/gavin/dev/hpcc/dali/base/dacsds.ipp:37
#9  0x00007f6ac8e8dd48 in Release<IRemoteConnection> (ptr=0x55bc30776a18) at /home/gavin/dev/hpcc/common/workunit/./../../system/jlib/jscm.hpp:46
#10 0x00007f6ac8e83850 in Shared<IRemoteConnection>::~Shared (this=0x55bc307785c8, __in_chrg=<optimised out>)
    at /home/gavin/dev/hpcc/common/workunit/./../../system/jlib/jscm.hpp:62
#11 0x00007f6ac8e58a0c in Owned<IRemoteConnection>::~Owned (this=0x55bc307785c8, __in_chrg=<optimised out>)
    at /home/gavin/dev/hpcc/common/workunit/./../../system/jlib/jscm.hpp:99
#12 0x00007f6ac8cb0fa9 in CLocalEnvironment::~CLocalEnvironment (this=0x55bc307785b0, __in_chrg=<optimised out>)
    at /home/gavin/dev/hpcc/common/environment/environment.cpp:1441
#13 0x00007f6ac8cb100a in CLocalEnvironment::~CLocalEnvironment (this=0x55bc307785b0, __in_chrg=<optimised out>)
    at /home/gavin/dev/hpcc/common/environment/environment.cpp:1445
#14 0x00007f6ac8523c35 in CInterfaceOf<CEmptyClass>::Release (this=0x55bc307785b8) at /home/gavin/dev/hpcc/system/jlib/jiface.hpp:160
#15 0x00007f6ac8523aeb in CInterface::Release (this=0x55bc307785b8) at /home/gavin/dev/hpcc/system/jlib/jiface.cpp:33
#16 0x00007f6ac8cc3741 in CLocalEnvironment::Release (this=0x55bc307785b0) at /home/gavin/dev/hpcc/common/environment/environment.cpp:299
#17 0x00007f6ac8caec8e in Release<IConstEnvironment> (ptr=0x55bc307785b0) at /home/gavin/dev/hpcc/common/environment/./../../system/jlib/jscm.hpp:46
#18 0x00007f6ac8cd1020 in Shared<IConstEnvironment>::clear (this=0x7f6ac8cf4040 <cache>)
    at /home/gavin/dev/hpcc/common/environment/./../../system/jlib/jscm.hpp:68
#19 0x00007f6ac8cc7281 in CEnvironmentFactory::close (this=0x55bc307768a0) at /home/gavin/dev/hpcc/common/environment/environment.cpp:724
#20 0x00007f6ac8cc6a83 in CEnvironmentFactory::~CEnvironmentFactory (this=0x55bc307768a0, __in_chrg=<optimised out>)
    at /home/gavin/dev/hpcc/common/environment/environment.cpp:678
#21 0x00007f6ac8cc6b50 in CEnvironmentFactory::~CEnvironmentFactory (this=0x55bc307768a0, __in_chrg=<optimised out>)
    at /home/gavin/dev/hpcc/common/environment/environment.cpp:679
#22 0x00007f6ac8523c35 in CInterfaceOf<CEmptyClass>::Release (this=0x55bc307768a0) at /home/gavin/dev/hpcc/system/jlib/jiface.hpp:160
#23 0x00007f6ac8523aeb in CInterface::Release (this=0x55bc307768a0) at /home/gavin/dev/hpcc/system/jlib/jiface.cpp:33
#24 0x00007f6ac8cc6605 in CEnvironmentFactory::Release (this=0x55bc307768a0) at /home/gavin/dev/hpcc/common/environment/environment.cpp:664
#25 0x00007f6ac8cd1492 in Release<CEnvironmentFactory> (ptr=0x55bc307768a0)
    at /home/gavin/dev/hpcc/common/environment/./../../system/jlib/jscm.hpp:46
#26 0x00007f6ac8cafb70 in _modExit792 () at /home/gavin/dev/hpcc/common/environment/environment.cpp:794
#27 0x00007f6ac853028a in InitTable::exit (this=0x55bc306f9eb0, ctx=0x0) at /home/gavin/dev/hpcc/system/jlib/jlib.cpp:110
#28 0x00007f6ac852fce4 in ExitModuleObjects (ctx=0x0) at /home/gavin/dev/hpcc/system/jlib/jlib.cpp:40
#29 0x00007f6ac852fd1e in ExitModuleObjects () at /home/gavin/dev/hpcc/system/jlib/jlib.cpp:46
#30 0x000055bc2f4db8a8 in EclccServer::run (this=0x7ffe2e49c4e0) at /home/gavin/dev/hpcc/ecl/eclccserver/eclccserver.cpp:756
#31 0x000055bc2f4d1e46 in main (argc=1, argv=0x7ffe2e49c698) at /home/gavin/dev/hpcc/ecl/eclccserver/eclccserver.cpp:953