[libSystem Crash]NWConcrete_nw_endpoint_flow updatePathWithHandler

[NWConcrete_nw_endpoint_flow updatePathWithHandler:]

libSystem crash with the following stack.It may happen when app is in background and doing network transmition.

SIGTRAP

Thread 8 Crashed: 0 libsystem_kernel.dylib 0x00000001829dae1c os_channel_create_extended + 1276 1 libsystem_network.dylib 0x0000000182a5c8f0 _nw_channel_create + 268 2 libsystem_network.dylib 0x0000000182a666f8 nw_channel_create_with_attributes + 208 3 libnetwork.dylib 0x0000000183e35748 _nw_endpoint_flow_attach_channel_protocol + 468 4 libnetwork.dylib 0x0000000183e330b4 _nw_endpoint_flow_attach_protocols + 7108 5 libnetwork.dylib 0x0000000183e30c18 _nw_endpoint_flow_setup_protocols + 128 6 libnetwork.dylib 0x0000000183e2fc48 _nw_endpoint_flow_setup_channel + 1268 7 libnetwork.dylib 0x0000000183e2e454 -[NWConcrete_nw_endpoint_flow updatePathWithHandler:] + 1588 8 libnetwork.dylib 0x0000000183e825c4 _nw_endpoint_handler_path_change + 4460 9 libnetwork.dylib 0x0000000183e81444 ___nw_endpoint_handler_start_block_invoke + 116 10 libsystem_network.dylib 0x0000000182b07f0c _nw_path_necp_update_evaluator + 1332 11 libsystem_network.dylib 0x0000000182b07960 _nw_path_necp_check_for_updates + 1124 12 libsystem_network.dylib 0x0000000182b13d0c nw_path_evaluator_request_nexus_and_stats + 520 13 libnetwork.dylib 0x0000000183e30460 _nw_endpoint_flow_setup_channel + 3340 14 libnetwork.dylib 0x0000000183e2d724 -[NWConcrete_nw_endpoint_flow startWithHandler:] + 4496 15 libnetwork.dylib 0x0000000183e83dd4 _nw_endpoint_handler_path_change + 10620 16 libnetwork.dylib 0x0000000183e8109c nw_endpoint_handler_start + 1164 17 libnetwork.dylib 0x0000000183ed8c24 _nw_endpoint_resolver_start_next_child + 3264 4 libdispatch.dylib 0x000000018284ca6c __dispatch_call_block_and_release + 24 5 libdispatch.dylib 0x000000018284ca2c __dispatch_client_callout + 16 20 libdispatch.dylib 0x00000001828569ac __dispatch_queue_serial_drain$VARIANT$mp + 608 21 libdispatch.dylib 0x00000001828572f4 __dispatch_queue_invoke$VARIANT$mp + 336 22 libdispatch.dylib 0x0000000182857cc0 __dispatch_root_queue_drain_deferred_wlh$VARIANT$mp + 340 23 libdispatch.dylib 0x0000000182860090 __dispatch_workloop_worker_thread$VARIANT$mp + 668 24 libsystem_pthread.dylib 0x0000000182b74f08 _pthread_wqthread + 852 1 libsystem_pthread.dylib 0x0000000182b74ba0 start_wqthread + 4

Never see this crash before, anyone has any idea???