Symptom:
Crash in mme-app with the following traceback
Program received signal SIGABRT, Aborted.
0xb7fff410 in __kernel_vsyscall ()       
(gdb) bt                                 
#0  0xb7fff410 in __kernel_vsyscall ()   
#1  0x14a08769 in raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#2  0x131eb260 in sn_assert (code=code@entry=ASSERT_GENERIC,                           
    xpr=xpr@entry=0x17e547b4 "!fsm_data->mfl_in_eh",                                   
    file=file@entry=0x17e52dd1 "sess/mme/mme-app/app/mme_fw.c", line=line@entry=427,   
    func=func@entry=0x17e33549 <__PRETTY_FUNCTION__.558074> "mme_fsm_event_handler",   
    msg=msg@entry=0x0) at snutil/sn_assert_handler.c:996                               
#3  0x0fdb2146 in mme_fsm_event_handler (app_inst=app_inst@entry=0x216b6a88,           
    fsm=fsm@entry=0x1b5d34c0 <mme_attach_fsm>, event=event@entry=0xbfffd1ec,           
    hdl=hdl@entry=0x8e840fa8) at sess/mme/mme-app/app/mme_fw.c:427                     
#4  0x0fde3207 in mme_event_handler_attach_procedure (app_inst=0x216b6a88,             
    context=context@entry=0x8e840fa8, event=event@entry=0xbfffd1ec)                    
    at sess/mme/mme-app/app/mme_attach_proc.c:3136                                     
#5  0x0fde32aa in mme_attach_proc_internal_event_handler (hdl=0x8e840fa8, event=0xbfffd1ec)
    at sess/mme/mme-app/app/mme_attach_proc.c:3479                                         
#6  0x0fd16fda in mme_end_procedure (event=event@entry=0xbfffd1ec, mpl=mpl@entry=0x8c2a7800)
    at sess/mme/mme-app/app/mme_fw.c:985                                                    
#7  0x0fd19496 in mme_auth_complete (mpl=mpl@entry=0x8c2a7800, cause=cause@entry=7 '\a')    
    at sess/mme/mme-app/app/mme_auth_proc.c:924                                             
#8  0x0fd611de in mme_auth_start_smc_with_null_security (ctxt=ctxt@entry=0x8e840fa8)        
    at sess/mme/mme-app/app/mme_auth_proc.c:1144                                            
#9  0x0fd65e0e in mme_auth_idle_imsi (hndl=0x8e840fa8, event=0x8c2cdf3c)                    
    at sess/mme/mme-app/app/mme_auth_proc.c:1627                                            
#10 0x0fdb226b in mme_fsm_event_handler (app_inst=app_inst@entry=0x216b6a88,                
    fsm=fsm@entry=0x1b5d3640 <mme_auth_fsm>, event=event@entry=0x8c2cdf3c,                  
    hdl=hdl@entry=0x8e840fa8) at sess/mme/mme-app/app/mme_fw.c:468                          
#11 0x0fde37ce in mme_start_auth_procedure (app_inst=0x216b6a88, hndl=0x8e840fa8,           
    event=0x8c2cdf3c) at sess/mme/mme-app/app/mme_auth_proc.c:4076                          
#12 0x0fcb2c32 in mme_start_procedure (app_inst=0x216b6a88,                                 
    procedure=procedure@entry=0x1b5d35e0 <mme_auth_procedure>, hdl=hdl@entry=0x8e840fa8,    
    event=event@entry=0x8c2cdf3c,                                                           
---Type <return> to continue, or q <return> to quit---                                      
    callback=callback@entry=0xfde3213 <mme_attach_proc_internal_event_handler>)             
    at sess/mme/mme-app/app/mme_fw.c:726                                                    
#13 0x0fe3049a in mme_attach_req_idle (hndl=0x8e840fa8, event=0x8c2cdf3c)                   
    at sess/mme/mme-app/app/mme_attach_proc.c:1198                                          
#14 0x0fdb226b in mme_fsm_event_handler (app_inst=app_inst@entry=0x216b6a88,                
    fsm=fsm@entry=0x1b5d34c0 <mme_attach_fsm>, event=event@entry=0x8c2cdf3c,                
    hdl=hdl@entry=0x8e840fa8) at sess/mme/mme-app/app/mme_fw.c:468                          
#15 0x0fde3523 in mme_start_attach_procedure (app_inst=0x216b6a88, hndl=0x8e840fa8,         
    event=0x8c2cdf3c) at sess/mme/mme-app/app/mme_attach_proc.c:3152                        
#16 0x0fcb2c32 in mme_start_procedure (app_inst=0x216b6a88,                                 
    procedure=0x1b5d3460 <mme_attach_procedure>, hdl=hdl@entry=0x8e840fa8,                  
    event=event@entry=0x8c2cdf3c, callback=callback@entry=0xfdf50f5 <mme_emm_procedure_callback>)
    at sess/mme/mme-app/app/mme_fw.c:726                                                         
#17 0x0fde4e09 in mme_disp_handle_emm_evt (ue_ctxt=ue_ctxt@entry=0x8e840fa8,                     
    event=event@entry=0x8c2cdf3c) at sess/mme/mme-app/app/mme_dispatcher_fsm.c:2371              
#18 0x0fdf6db4 in mme_disp_ncall_arrived_handle_smgr_event (disp_fsm_hdl=0x8e840fa8,             
    event=0xbfffe98c) at sess/mme/mme-app/app/mme_dispatcher_fsm.c:3404                          
#19 0x0fdb226b in mme_fsm_event_handler (app_inst=0x216b6a88,                                    
    fsm=fsm@entry=0x1b5d3560 <mme_dispatcher_fsm>, event=event@entry=0xbfffe98c,                 
    hdl=hdl@entry=0x8e840fa8) at sess/mme/mme-app/app/mme_fw.c:468                               
#20 0x0fde44cd in mme_app_handle_answer_call (mme_drv_instp=mme_drv_instp@entry=0x21656130,      
    snx_msg=snx_msg@entry=0xbffff368) at sess/mme/mme-app/app/mme_app_smgr.c:223                 
#21 0x0fc7f60a in snx_mme_app_driver_request_control_dispatch (priv=0x21656130, msg=0xbffff368)  
    at sess/snx/drivers/mme-app/mme_app_drv.c:345                                                
#22 0x0b17434b in smgr_fsm_newcall_arrived (clp=clp@entry=0x8d0357dc,                            
    event=event@entry=SMGR_EVT_ANSWER_CALL, msg=msg@entry=0xbffff368)                            
    at sess/smgr/sessmgr_fsm.c:745                                                               
#23 0x0b175bc2 in smgr_callline_fsm (clp=0x8d0357dc, event=SMGR_EVT_ANSWER_CALL,                 
    fsm_msg=0xbffff368) at sess/smgr/sessmgr_fsm.c:226                                           
#24 0x0be2f66d in sessmgr_mme_send_answer_call (sap=2365806556, ident=0, seqno=1)                
    at sess/smgr/sessmgr_mme.c:2579

Conditions:
When UE initiates an emergency call with network capability not containing EIA0 and EEA0 and mobile identity as IMSI.