Core was generated by `nginx:'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x0000555c3ace3b7e in ngx_rbtree_min (node=0x0, sentinel=0x555c3ae2f720 <ngx_event_timer_sentinel>) at src/core/ngx_rbtree.h:76
76 while (node->left != sentinel) {
[Current thread is 1 (LWP 8)]
(gdb) bt
#0 0x0000555c3ace3b7e in ngx_rbtree_min (node=0x0, sentinel=0x555c3ae2f720 <ngx_event_timer_sentinel>) at src/core/ngx_rbtree.h:76
#1 0x0000555c3ace3c87 in ngx_event_expire_timers () at src/event/ngx_event_timer.c:68
#2 0x0000555c3ace1118 in ngx_process_events_and_timers (cycle=0x555c3bd46650) at src/event/ngx_event.c:266
#3 0x0000555c3acf4329 in ngx_worker_process_cycle (cycle=0x555c3bd46650, data=0x0) at src/os/unix/ngx_process_cycle.c:812
#4 0x0000555c3aceff2d in ngx_spawn_process (cycle=0x555c3bd46650, proc=0x555c3acf41fe <ngx_worker_process_cycle>, data=0x0, name=0x555c3addb9cd "worker process", respawn=-3) at src/os/unix/ngx_process.c:199
#5 0x0000555c3acf2d35 in ngx_start_worker_processes (cycle=0x555c3bd46650, n=8, type=-3) at src/os/unix/ngx_process_cycle.c:388
#6 0x0000555c3acf1fe8 in ngx_master_process_cycle (cycle=0x555c3bd46650) at src/os/unix/ngx_process_cycle.c:136
#7 0x0000555c3aca4f77 in main (argc=1, argv=0x7ffcd3346468) at src/core/nginx.c:385