Persistent connections cause signal 11 when no matching connection is found

2020-12-16 13:50:37   alert  : (24) (db3) MaxScale 2.5.6 received fatal signal 11. Commit ID: fddc0526ee79ac9a87f7a7170f3204263240ab57 System name: Linux Release string: NAME="CentOS Linux"

2020-12-16 13:50:37   alert  : (24) (db3) Statement currently being classified: none/unknown

2020-12-16 13:50:39   alert  : (24) (db3)

  /usr/lib64/maxscale/libmaxscale-common.so.1.0.0(_ZN8maxscale13RoutingWorker25get_backend_dcb_from_poolEP6SERVERP11MXS_SESSIONPNS_9ComponentE+0x200): server/core/routingworker.cc:568

  /usr/lib64/maxscale/libmaxscale-common.so.1.0.0(_ZN8maxscale13RoutingWorker15get_backend_dcbEP6SERVERP11MXS_SESSIONPNS_9ComponentE+0x91): server/core/routingworker.cc:530

  /usr/lib64/maxscale/libmaxscale-common.so.1.0.0(_ZN14ServerEndpoint7connectEv+0x7d): server/core/server.cc:932 (discriminator 1)

  /usr/lib64/maxscale/libmaxscale-common.so.1.0.0(_ZN8maxscale7Backend7connectEPSt4listISt10shared_ptrINS_14SessionCommandEESaIS4_EE+0x1f): server/core/backend.cc:174

  /usr/lib64/maxscale/libreadwritesplit.so(_ZN14RWSplitSession18prepare_connectionEPN8maxscale9RWBackendE+0x19): server/modules/routing/readwritesplit/rwsplit_route_stmt.cc:48

  /usr/lib64/maxscale/libreadwritesplit.so(_ZN14RWSplitSession16open_connectionsEv+0x5a4): server/modules/routing/readwritesplit/rwsplit_select_backends.cc:463

  /usr/lib64/maxscale/libreadwritesplit.so(_ZN14RWSplitSession6createEP7RWSplitP11MXS_SESSIONRKSt6vectorIPN8maxscale8EndpointESaIS7_EE+0x131): server/modules/routing/readwritesplit/rwsplitsession.cc:67

  /usr/lib64/maxscale/libreadwritesplit.so(_ZN8maxscale6RouterI7RWSplit14RWSplitSessionE10newSessionEP10mxs_routerP11MXS_SESSIONPNS_8UpstreamERKSt6vectorIPNS_8EndpointESaISC_EE+0x14): include/maxscale/router.hh:404

  /usr/lib64/maxscale/libmaxscale-common.so.1.0.0(_ZN15ServiceEndpoint7connectEv+0x10d): server/core/service.cc:1291

  /usr/lib64/maxscale/libmaxscale-common.so.1.0.0(_ZN7Session5startEv+0x21): server/core/session.cc:1283

  /usr/lib64/maxscale/libmariadbclient.so(_ZN23MariaDBClientConnection22process_authenticationENS_8AuthTypeE+0x319): server/modules/protocol/MariaDB/mariadb_client.cc:615

  /usr/lib64/maxscale/libmariadbclient.so(_ZN23MariaDBClientConnection17ready_for_readingEP3DCB+0x39): server/modules/protocol/MariaDB/mariadb_client.cc:1418

  /usr/lib64/maxscale/libmaxscale-common.so.1.0.0(_ZN3DCB14process_eventsEj+0x69): server/core/dcb.cc:1292

  /usr/lib64/maxscale/libmaxscale-common.so.1.0.0(_ZN3DCB13event_handlerEPS_j+0x21): server/core/dcb.cc:1351

  /usr/lib64/maxscale/libmaxscale-common.so.1.0.0(_ZN7maxbase6Worker15poll_waiteventsEv+0x1be): maxutils/maxbase/src/worker.cc:879

  /usr/lib64/maxscale/libmaxscale-common.so.1.0.0(_ZN7maxbase6Worker3runEPNS_9SemaphoreE+0x53): maxutils/maxbase/src/worker.cc:574

  /usr/lib64/maxscale/libmaxscale-common.so.1.0.0(+0x228a0f): thread48.o:?

  /lib64/libpthread.so.0(+0x7ea5): pthread_create.c:?

  /lib64/libc.so.6(clone+0x6d): ??:?