as a client , connect an non-existent address which in the same subnet, when establish timer is timeout , there will be a segment fault in tcp_expired_timers_dispatch. details As follow:

Maybe there is a null pointer here : track=0x38.
TCP_EVT_TIMER_POP_HANDLER has some little issue.

#0 elog_event_data_inline (cpu_time=60947086043199, track=0x38, type=type@entry=0x7ffff7906f60 <_e.25034>, em=0x7ffff7bb25a8 <vlib_global_main+776>,
em@entry=0x7ffff7bb28b0 <vlib_thread_main+16>) at /home/wanghui/vpp_git/vpp/build-data/../src/vppinfra/elog.h:303
#1 elog_event_data (em=em@entry=0x7ffff7bb25a8 <vlib_global_main+776>, type=type@entry=0x7ffff7906f60 <_e.25034>, track=0x38,
cpu_time=60947086043199) at /home/wanghui/vpp_git/vpp/build-data/../src/vppinfra/elog.c:68
#2 0x00007ffff748b77c in elog_event_data_not_inline (cpu_time=<optimized out>, track=<optimized out>, type=0x7ffff7906f60 <_e.25034>,
em=<optimized out>) at /home/wanghui/vpp_git/vpp/build-data/../src/vppinfra/elog.h:356
#3 elog_data (track=<optimized out>, type=0x7ffff7906f60 <_e.25034>, em=<optimized out>)
at /home/wanghui/vpp_git/vpp/build-data/../src/vppinfra/elog.h:426
#4 tcp_expired_timers_dispatch (expired_timers=0x7fffb628e24c) at /home/wanghui/vpp_git/vpp/build-data/../src/vnet/tcp/tcp.c:740
#5 0x00007ffff68032a2 in tw_timer_expire_timers_16t_2w_512sl (tw=0x7fffb6304534, now=<optimized out>)
at /home/wanghui/vpp_git/vpp/build-data/../src/vppinfra/tw_timer_template.c:330
#6 0x00007ffff75a5b1c in tcp_update_time (thread_index=0, now=<optimized out>) at /home/wanghui/vpp_git/vpp/build-data/../src/vnet/tcp/tcp.h:498
#7 session_queue_node_fn (vm=0x7ffff7bb22a0 <vlib_global_main>, node=0x7fffb5f19800, frame=<optimized out>)
at /home/wanghui/vpp_git/vpp/build-data/../src/vnet/session/node.c:342
#8 0x00007ffff795f8ab in dispatch_node (last_time_stamp=60947086039767, frame=0x0, dispatch_state=VLIB_NODE_STATE_POLLING,
type=VLIB_NODE_TYPE_INPUT, node=0x7fffb5f19800, vm=0x7ffff7bb22a0 <vlib_global_main>)
at /home/wanghui/vpp_git/vpp/build-data/../src/vlib/main.c:998
#9 vlib_main_or_worker_loop (is_main=1, vm=0x7ffff7bb22a0 <vlib_global_main>) at /home/wanghui/vpp_git/vpp/build-data/../src/vlib/main.c:1499
#10 vlib_main_loop (vm=0x7ffff7bb22a0 <vlib_global_main>) at /home/wanghui/vpp_git/vpp/build-data/../src/vlib/main.c:1621
#11 vlib_main (vm=vm@entry=0x7ffff7bb22a0 <vlib_global_main>, input=input@entry=0x7fffb5ea9fa0)
at /home/wanghui/vpp_git/vpp/build-data/../src/vlib/main.c:1749
#12 0x00007ffff79997f3 in thread0 (arg=140737349624480) at /home/wanghui/vpp_git/vpp/build-data/../src/vlib/unix/main.c:507
#13 0x00007ffff67d5e20 in clib_calljmp () at /home/wanghui/vpp_git/vpp/build-data/../src/vppinfra/longjmp.S:110
#14 0x00007fffffffd270 in ?? ()
#15 0x00007ffff799a289 in vlib_unix_main (argc=<optimized out>, argv=<optimized out>)
at /home/wanghui/vpp_git/vpp/build-data/../src/vlib/unix/main.c:570
#16 0x0000000500000004 in ?? ()
#17 0x662d326c00000010 in ?? ()
#18 0x3a6c6c61632d6477 in ?? ()
#19 0x0000000500642520 in ?? ()
#20 0xf731373000000046 in ?? ()
#21 0xb5ed6d6c00007fff in ?? ()
#22 0x000011ac00007fff in ?? ()
#23 0x0000000000000000 in ?? ()