sysbench crash at script_lua.c:860

1. Sysbench crashed when executing a lua script which without 'END' used right.

2. Crash information is as bellow.
(gdb) bt
#0 sb_lua_db_execute (L=0x23317f0) at script_lua.c:860
#1 0x00000000004198c4 in luaD_precall (L=0x23317f0, func=<value optimized out>, nresults=<value optimized out>) at ldo.c:319
#2 0x0000000000428db9 in luaV_execute (L=<value optimized out>, nexeccalls=1) at lvm.c:587
#3 0x000000000041a32d in luaD_call (L=0x23317f0, func=0x2331bf0, nResults=<value optimized out>) at ldo.c:377
#4 0x0000000000419327 in luaD_rawrunprotected (L=0x23317f0, f=0x416770 <f_call>, ud=0x7fff13dcbd80) at ldo.c:116
#5 0x00000000004193a2 in luaD_pcall (L=0x23317f0, func=<value optimized out>, u=<value optimized out>, old_top=64, ef=<value optimized out>) at ldo.c:461
#6 0x00000000004163df in lua_pcall (L=0x23317f0, nargs=0, nresults=0, errfunc=<value optimized out>) at lapi.c:817
#7 0x000000000041221d in sb_lua_new_state (scriptname=0x2330750 "./tests/db/ob_oltp_ps.lua", thread_id=-1) at script_lua.c:479
#8 0x000000000041228a in script_load_lua (testname=0x2330750 "./tests/db/ob_oltp_ps.lua", test=0x89a140) at script_lua.c:172
#9 0x00000000004118bd in script_load (testname=0x2330750 "./tests/db/ob_oltp_ps.lua") at sb_script.c:37
#10 0x0000000000407ad8 in main (argc=<value optimized out>, argv=<value optimized out>) at sysbench.c:1152

3. Example test file like this:

pathtest = string.match(test, "(.*/)") or ""

dofile(pathtest .. "ob_common.lua")

function thread_init(thread_id)
   set_vars()
end

function event(thread_id)
   end
   if not oltp_skip_trx then
      db_query("begin")
   end