MME crashes when FEG restart (CSFB)

[uri200]

Every time magma starts, it sends reset to VLR through CSFB service. VLR responds with Restart acknowledge. Then FEG forwards that to MME.

It looks like MME is not handling this restart properly and crashes

As a workaround we are disabling CSFB on FEG

Oct 23 11:42:49 magma-ag mme[49649]: Server running (127.0.0.1:6654)
Oct 23 11:42:49 magma-ag mme[49649]: [/home/vagrant/magma/orc8r/gateway/c/common/config/ServiceConfigLoader.cpp:34] Override file not found for service redis
Oct 23 11:42:50 magma-ag mme[49649]: [DEBUG] Success logging event: s1_setup_success
Oct 23 11:43:57 magma-ag mme[49649]: Assertion (task_zmq_ctx_p->push_socks[destination_task_id]) failed!
Oct 23 11:43:57 magma-ag mme[49649]: In send_msg_to_task() /home/vagrant/magma/lte/gateway/c/oai/lib/itti/intertask_interface.c:125
Oct 23 11:43:57 magma-ag mme[49649]: Sending to task without push socket. id: SGSAP_VLR_RESET_INDICATION to TASK_MME_APP!
Oct 23 11:43:57 magma-ag mme[49649]:  Will Intentionaly raise SEGFAULT to be catched by GDB!
Oct 23 11:43:57 magma-ag mme[49649]: Obtained 10 stack frames.
Oct 23 11:43:57 magma-ag mme[49649]: /usr/local/bin/mme(display_backtrace+0x20) [0x55a0e9193ce5]
Oct 23 11:43:57 magma-ag mme[49649]: /usr/local/bin/mme(send_msg_to_task+0x118) [0x55a0e96d339b]
Oct 23 11:43:57 magma-ag mme[49649]: /usr/local/bin/mme(handle_sgs_vlr_reset_indication+0xe1) [0x55a0e9556770]
Oct 23 11:43:57 magma-ag mme[49649]: /usr/local/bin/mme(_ZN5magma22CSFBGatewayServiceImpl18VLRResetIndicationEPN4grpc13ServerContextEPKNS_3feg15ResetIndicationEPNS_5orc8r4VoidE+0x56) [0x55a0e9383636]
Oct 23 11:43:57 magma-ag mme[49649]: /usr/local/bin/mme(_ZSt13__invoke_implIN4grpc6StatusERKMN5magma3feg18CSFBGatewayService7ServiceEFS1_PNS0_13ServerContextEPKNS3_15ResetIndicationEPNS2_5orc8r4VoidEEPS5_JS7_SA_SD_EET_St21__invoke_memfun_derefOT0_OT1_DpOT2_+0xb5) [0x55a0e935d709]
Oct 23 11:43:57 magma-ag mme[49649]: /usr/local/bin/mme(_ZSt8__invokeIRKMN5magma3feg18CSFBGatewayService7ServiceEFN4grpc6StatusEPNS4_13ServerContextEPKNS1_15ResetIndicationEPNS0_5orc8r4VoidEEJPS3_S7_SA_SD_EENSt9result_ofIFOT_DpOT0_EE4typeESL_SO_+0x92) [0x55a0e935bcc2]
Oct 23 11:43:57 magma-ag mme[49649]: /usr/local/bin/mme(_ZNKSt12_Mem_fn_baseIMN5magma3feg18CSFBGatewayService7ServiceEFN4grpc6StatusEPNS4_13ServerContextEPKNS1_15ResetIndicationEPNS0_5orc8r4VoidEELb1EEclIJPS3_S7_SA_SD_EEEDTcl8__invokedtdefpT6_M_pmfspcl7forwardIT_Efp_EEEDpOSJ_+0x7a) [0x55a0e93590f8]
Oct 23 11:43:57 magma-ag mme[49649]: /usr/local/bin/mme(_ZNSt17_Function_handlerIFN4grpc6StatusEPN5magma3feg18CSFBGatewayService7ServiceEPNS0_13ServerContextEPKNS3_15ResetIndicationEPNS2_5orc8r4VoidEESt7_Mem_fnIMS5_FS1_S8_SB_SE_EEE9_M_invokeERKSt9_Any_dataOS6_OS8_OSB_OSE_+0x8a) [0x55a0e9355975]
Oct 23 11:43:57 magma-ag mme[49649]: /usr/local/bin/mme(_ZNKSt8functionIFN4grpc6StatusEPN5magma3feg18CSFBGatewayService7ServiceEPNS0_13ServerContextEPKNS3_15ResetIndicationEPNS2_5orc8r4VoidEEEclES6_S8_SB_SE_+0x96) [0x55a0e936983c]
Oct 23 11:43:57 magma-ag mme[49649]: /usr/local/bin/mme(_ZZN4grpc8internal16RpcMethodHandlerIN5magma3feg18CSFBGatewayService7ServiceENS3_15ResetIndicationENS2_5orc8r4VoidEE10RunHandlerERKNS0_13MethodHandler16HandlerParameterEENKUlvE_clEv+0x54) [0x55a0e93631ee]
Oct 23 11:43:59 magma-ag systemd[1]: magma@mme.service: Main process exited, code=killed, status=11/SEGV
Oct 23 11:44:00 magma-ag systemd[1]: magma@mme.service: Unit entered failed state.
Oct 23 11:44:00 magma-ag systemd[1]: magma@mme.service: Failed with result 'signal'.
Oct 23 11:44:05 magma-ag systemd[1]: magma@mme.service: Service hold-off time over, scheduling restart.
Oct 23 11:44:05 magma-ag systemd[1]: Stopped Magma OAI MME service.
Oct 23 11:44:06 magma-ag systemd[1]: Starting Magma OAI MME service...
Oct 23 11:44:06 magma-ag mme[51391]: ERROR:root:Error retrieving config for mme, key not found: enable_nat