fix crash, same as #26.
fix crash, same as #26.

shrimpz/slua,luzexi/slua-3rd,haolly/slua_source_note,dayongxie/slua,LacusCon/slua,soulgame/slua,haolly/slua_source_note,haolly/slua_source_note,thing-nacho/slua,luzexi/slua-3rd-lib,luzexi/slua-3rd-lib,Roland0511/slua,luzexi/slua-3rd-lib,luzexi/slua-3rd-lib,chiuan/slua,luzexi/slua-3rd-lib,DebugClub/slua,yaukeywang/slua,Roland0511/slua,lingkeyang/slua,Salada/slua,jiangzhhhh/slua,angeldnd/slua,DebugClub/slua,DebugClub/slua,soulgame/slua,chiuan/slua,DebugClub/slua,yaukeywang/slua,dayongxie/slua,zhukunqian/slua-1,soulgame/slua,luzexi/slua-3rd,pangweiwei/slua,lingkeyang/slua,yaukeywang/slua,zhukunqian/slua-1,mr-kelly/slua,luzexi/slua-3rd,DebugClub/slua,pangweiwei/slua,chiuan/slua,luzexi/slua-3rd,luzexi/slua-3rd,zhukunqian/slua-1,LacusCon/slua,haolly/slua_source_note,soulgame/slua,Salada/slua,angeldnd/slua,luzexi/slua-3rd,chiuan/slua,LacusCon/slua,zhukunqian/slua-1,haolly/slua_source_note,chiuan/slua,pangweiwei/slua,angeldnd/slua,dayongxie/slua,yaukeywang/slua,LacusCon/slua,Salada/slua,thing-nacho/slua,chiuan/slua,Roland0511/slua,LacusCon/slua,jiangzhhhh/slua,LacusCon/slua,pangweiwei/slua,mr-kelly/slua,pangweiwei/slua,thing-nacho/slua,jiangzhhhh/slua,DebugClub/slua,angeldnd/slua,Roland0511/slua,mr-kelly/slua,soulgame/slua,mr-kelly/slua,thing-nacho/slua,jiangzhhhh/slua,lingkeyang/slua,jiangzhhhh/slua,Salada/slua,Salada/slua,lingkeyang/slua,luzexi/slua-3rd-lib,angeldnd/slua,lingkeyang/slua,thing-nacho/slua,angeldnd/slua,shrimpz/slua,Roland0511/slua,Salada/slua,dayongxie/slua,haolly/slua_source_note,mr-kelly/slua,thing-nacho/slua,jiangzhhhh/slua,soulgame/slua,Roland0511/slua,yaukeywang/slua,zhukunqian/slua-1,dayongxie/slua,mr-kelly/slua,yaukeywang/slua,lingkeyang/slua