python+selenium+phantomjs中经常会出现phantomjs占cpu过高的情况，怎么办？

Question

用途：爬虫（框架：scrapy）

            cap = dict(DesiredCapabilities.PHANTOMJS)
            cap["phantomjs.page.settings.resourceTimeout"] = 1000
            cap["phantomjs.page.settings.loadImages"] = False
            cap["phantomjs.page.settings.webSecurityEnabled"] = False
            driver = webdriver.PhantomJS(executable_path='/usr/local/bin/phantomjs',desired_capabilities=cap)
            driver.set_page_load_timeout(20)
            driver.set_script_timeout(20)
            
            try:
               driver.get(request.url)

            except Exception as e:
               print e
            finally:
               driver.quit()
               
发现phantomjs经常quit不掉，以致cpu越来越高，pgrep phantomjs,phantomjs一大堆。
个人认为，driver.get(request.url)，一旦遇到js的坑，就会死在这儿，从而phantomjs也就无法quit。
请问大家有无好办法？