SetLength(Var,10) 内存溢出? 诡异的问题(100分)

function PsList:String;
var
    List:Tstringlist;
    isOK:Boolean;
    ProcessHandle:Thandle;
    ProcessStruct:TProcessEntry32;
    Ps,Pid:String;
begin
     List:=Tstringlist.Create;  //创建列表
     ProcessHandle:=createtoolhelp32snapshot(Th32cs_snapprocess,0);  //快照
     processStruct.dwSize:=sizeof(ProcessStruct);  //设置
     isOK:=process32first(ProcessHandle,ProcessStruct);  //初始化
     List.Add('PID' +'         '+ 'Process'); //第一行,
     while isOK do  //循环
     begin
     Ps:=ProcessStruct.szExeFile;  //进程名
     Pid:=IntToStr(ProcessStruct.th32ProcessID); //进程PID
     SetLength(Pid,12);   //固定长度

	  //   IntToStr(ProcessStruct.cntThreads));//线程数--------3
	  //   IntToStr(ProcessStruct.pcPriClassBase));//优先级-4
	  //   IntToStr(ProcessStruct.th32ParentProcessID));//父进程ID-5
     //List.Add(Pid+PsPath(StrToInt(Pid)));
              List.Add(Pid+'AAAAAAAAAAAAAA');
	   isOK:=process32next(ProcessHandle,ProcessStruct);
     end;
     Result:=List.text;
     CloseHandle(ProcessHandle);
     List.Free;
end;