gdb full backtrace for nginx signal 11

gistfile1.txt

(gdb) c
Continuing.

Program received signal SIGSEGV, Segmentation fault.
ngx_http_lua_socket_keepalive_close_handler (ev=0x1562948) at ../ngx_lua-0.9.6/src/ngx_http_lua_socket_tcp.c:3927
3927        spool = item->socket_pool;
(gdb) bt full
#0  ngx_http_lua_socket_keepalive_close_handler (ev=0x1562948) at ../ngx_lua-0.9.6/src/ngx_http_lua_socket_tcp.c:3927
        item = 0x40828c7f
        spool = <value optimized out>
        n = <value optimized out>
        buf = ""
        c = 0x1530a58
#1  0x00000000004a7ee2 in ngx_http_lua_socket_keepalive_rev_handler (ev=<value optimized out>)
    at ../ngx_lua-0.9.6/src/ngx_http_lua_socket_tcp.c:3877
No locals.
#2  0x000000000042d50f in ngx_event_expire_timers () at src/event/ngx_event_timer.c:151
        ev = 0x1562948
        node = 0x1562970
        root = 0x706960
        sentinel = 0x706960
#3  0x000000000042d3ff in ngx_process_events_and_timers (cycle=0x14e7ca0) at src/event/ngx_event.c:264
        flags = 1
        timer = <value optimized out>
        delta = 966
#4  0x0000000000432ff9 in ngx_worker_process_cycle (cycle=0x14e7ca0, data=<value optimized out>)
    at src/os/unix/ngx_process_cycle.c:816
        worker = <value optimized out>
        i = <value optimized out>
        c = <value optimized out>
#5  0x00000000004318e4 in ngx_spawn_process (cycle=0x14e7ca0, proc=0x432f26 <ngx_worker_process_cycle>, data=0x0,
    name=0x4c5cc6 "worker process", respawn=-4) at src/os/unix/ngx_process.c:198
        on = 1
        pid = 0
        s = 0
#6  0x0000000000432530 in ngx_start_worker_processes (cycle=0x14e7ca0, n=1, type=-4)
    at src/os/unix/ngx_process_cycle.c:364
---Type <return> to continue, or q <return> to quit---
        i = <value optimized out>
        ch = {command = 1, pid = 0, slot = 0, fd = 0}
#7  0x0000000000433b55 in ngx_master_process_cycle (cycle=0x14e7ca0) at src/os/unix/ngx_process_cycle.c:249
        title = <value optimized out>
        p = <value optimized out>
        size = <value optimized out>
        i = <value optimized out>
        n = <value optimized out>
        sigio = 0
        set = {__val = {0 <repeats 16 times>}}
        itv = {it_interval = {tv_sec = 21955672, tv_usec = 0}, it_value = {tv_sec = 0, tv_usec = 0}}
        live = 1
        delay = 0
        ls = <value optimized out>
        ccf = 0x14e8298
#8  0x0000000000418af4 in main (argc=<value optimized out>, argv=<value optimized out>) at src/core/nginx.c:407
        i = <value optimized out>
        log = 0x704760
        cycle = 0x14a94d0
        init_cycle = {conf_ctx = 0x0, pool = 0x14a89c0, log = 0x704760, new_log = {log_level = 0, file = 0x0,
            connection = 0, handler = 0, data = 0x0, action = 0x0, next = 0x0}, log_use_stderr = 0, files = 0x0,
          free_connections = 0x0, free_connection_n = 0, reusable_connections_queue = {prev = 0x0, next = 0x0},
          listening = {elts = 0x0, nelts = 0, size = 0, nalloc = 0, pool = 0x0}, paths = {elts = 0x0, nelts = 0,
            size = 0, nalloc = 0, pool = 0x0}, open_files = {last = 0x0, part = {elts = 0x0, nelts = 0, next = 0x0},
            size = 0, nalloc = 0, pool = 0x0}, shared_memory = {last = 0x0, part = {elts = 0x0, nelts = 0, next = 0x0},
            size = 0, nalloc = 0, pool = 0x0}, connection_n = 0, files_n = 0, connections = 0x0, read_events = 0x0,
          write_events = 0x0, old_cycle = 0x0, conf_file = {len = 36, data = 0x14a8a25 ""}, conf_param = {len = 0,
            data = 0x0}, conf_prefix = {len = 26, data = 0x14a8a25 ""}, prefix = {len = 21, data = 0x14a8a10 ""},
          lock_file = {len = 0, data = 0x0}, hostname = {len = 0, data = 0x0}}
        ccf = <value optimized out>
(gdb)