[jira] [Created] (ZOOKEEPER-2111) Not isAlive states should be synchronized in ClientCnxn

["Hongchao Deng (JIRA)" <ji...@apache.org>]

Hongchao Deng created ZOOKEEPER-2111:
----------------------------------------

             Summary: Not isAlive states should be synchronized in ClientCnxn
                 Key: ZOOKEEPER-2111
                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2111
             Project: ZooKeeper
          Issue Type: Bug
          Components: java client
            Reporter: Hongchao Deng
            Assignee: Hongchao Deng


In ClientCnxn.queuePacket, it checks variables of state and closing and then make decisions. There is toctou race in queuePacket():
{code}
        if (!state.isAlive() || closing) {
            conLossPacket(packet);
        } else {
            ...
        }
{code}

A possible race:
in SendThread.run():
{code}
  while (state.isAlive()) {
    ...
  }
  cleanup();
{code}

When it checks in queuePacket(), state is still alive. Then state isn't alive, SendThread.run() cleans up outgoingQueue. Then queuePacket adds packet to outgoingQueue. The packet should be waken up with exception. But it won't at this case.



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