[jira] [Created] (THRIFT-3891) TNonblockingServer does not return from {{serve()}} upon {{stop()}} with more than one IO threads

["Buğra Gedik (JIRA)" <ji...@apache.org>]

Buğra Gedik created THRIFT-3891:
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             Summary: TNonblockingServer does not return from {{serve()}} upon {{stop()}} with more than one IO threads
                 Key: THRIFT-3891
                 URL: https://issues.apache.org/jira/browse/THRIFT-3891
             Project: Thrift
          Issue Type: Bug
          Components: C++ - Library
    Affects Versions: 0.9.3
            Reporter: Buğra Gedik
            Priority: Minor


When the number of IO threads is > 1, there is race condition in which {{stop()}} does not properly unblock {{serve()}}. 

The problem manifests itself when {{stop()}} is called soon after {{serve()}}. 

The core issue is that, {{event_base_loopbreak()}} is called within the {{stop()}} sequence without checking whether the IO thread has actually entered its loop. The documentation of {{event_base_loopbreak()}} says (http://www.wangafu.net/~nickm/libevent-book/Ref3_eventloop.html)

{quote}
Note also that event_base_loopexit(base,NULL) and event_base_loopbreak(base) act differently when no event loop is running: loopexit schedules the next instance of the event loop to stop right after the next round of callbacks are run (as if it had been invoked with EVLOOP_ONCE) whereas loopbreak only stops a currently running loop, and has no effect if the event loop isn’t running.
{quote}

Attached is a patch.




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