Symptom:
Crash in
[076c8817/X] egtpc_unbind_user_sap() sp=0xffffb198
[051a774c/X] sgwdrv_deallocate_pdn() sp=0xffffb208
[051a7bd1/X] sgwdrv_deallocate_callline() sp=0xffffb258
[051a81fb/X] sgwdrv_close() sp=0xffffb2a8
[045667d0/X] snx_driver_close() sp=0xffffb2e8
[05cf4d4b/X] sessmgr_snx_unplumb_stack() sp=0xffffb338
[03512a52/X] sessmgr_terminate_service() sp=0xffffb398

Conditions:
i) A Collapsed Call is relocated to 3g from LTE .
ii) Delete Session Request is not yet received so we have Sessmgr clp as GGSN with SGW side still there.
iii) SGW service is stopped (due to switchover/PSC card migration/done by admin), which causes cleanup of call via posting abort. However, as the call become GGSN , abort is not posted on it.
iv) When drivers are cleaned up (sgw/saegw) they are cleaned up locally, which causes session hanging at egtpc.
v) When egptc layer is cleaning up, it sees some pdn session for UE, which shouldn't be there and crashes.