org.apache.zookeeper.server.NettyServerCnxn does not increase outstandingCount properly, cause outstandingCount to overflow.

In the receiveMessage method the count is increased right after processPacket without judges anything as below.

if (initialized) {
// TODO: if zks.processPacket() is changed to take a ByteBuffer[],
// we could implement zero-copy queueing.
zks.processPacket(this, bb);

if (zks.shouldThrottle(outstandingCount.incrementAndGet()))

Unknown macro: { disableRecvNoWait(); }

}

But after the request is handled, the decrease operation is taken only when xid is larger than 0.

@Override
public void sendResponse(ReplyHeader h, Record r, String tag)
throws IOException
Unknown macro: { if (closingChannel || !channel.isOpen()) Unknown macro}
super.sendResponse(h, r, tag);
if (h.getXid() > 0)
Unknown macro: { // zks cannot be null otherwise we would not have gotten here! if (!zkServer.shouldThrottle(outstandingCount.decrementAndGet())) Unknown macro}
}
}

So the bultin xids like "PING", "AUTH", will make outstandingCount larger and larger, until it hits the limit; All the request on that connection will be refused.

I see the problem is solved in 3.6.0 version, should there be a patch for 3.5.9? Looking forward for your reply, Thantks!