Deadlock between WsRemoteEndpointImplServer.onWritePossible and Http11NioProcessor.writeEvent

Issue

• We see a deadlock between the following:

"Thread-2":
    at org.apache.coyote.http11.Http11NioProcessor.writeEvent(Http11NioProcessor.java:760)
    - waiting to lock <0x00000007916bfb58> (a org.apache.coyote.http11.Http11NioProcessor)
    at org.apache.coyote.http11.Http11NioProcessor.action(Http11NioProcessor.java:859)
    at org.apache.coyote.Response.action(Response.java:188)
    at org.apache.catalina.connector.OutputBuffer.lastWrite(OutputBuffer.java:392)
    at org.apache.catalina.connector.CoyoteOutputStream.isReady(CoyoteOutputStream.java:112)
    at org.apache.tomcat.websocket.server.WsRemoteEndpointImplServer.onWritePossible(WsRemoteEndpointImplServer.java:89)
    - locked <0x0000000791cd1928> (a java.lang.Object)
    at org.apache.tomcat.websocket.server.WsRemoteEndpointImplServer.doWrite(WsRemoteEndpointImplServer.java:75)
    at org.apache.tomcat.websocket.WsRemoteEndpointImplBase.writeMessagePart(WsRemoteEndpointImplBase.java:445)
    at org.apache.tomcat.websocket.WsRemoteEndpointImplBase.startMessage(WsRemoteEndpointImplBase.java:335)
    at org.apache.tomcat.websocket.WsRemoteEndpointImplBase$TextMessageSendHandler.write(WsRemoteEndpointImplBase.java:741)
    - locked <0x0000000791cd1928> (a java.lang.Object)
    at org.apache.tomcat.websocket.WsRemoteEndpointImplBase.sendPartialString(WsRemoteEndpointImplBase.java:240)
    at org.apache.tomcat.websocket.WsRemoteEndpointImplBase.sendString(WsRemoteEndpointImplBase.java:183)
    at org.apache.tomcat.websocket.WsRemoteEndpointBasic.sendText(WsRemoteEndpointBasic.java:37)
    at abc.app.run(ShellWorker.java:90)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask.run(FutureTask.java:262)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)
"http-executor-threads - 17":
    at org.apache.tomcat.websocket.server.WsRemoteEndpointImplServer.onWritePossible(WsRemoteEndpointImplServer.java:80)
    - waiting to lock <0x0000000791cd1928> (a java.lang.Object)
    at org.apache.tomcat.websocket.server.WsHttpUpgradeHandler$WsWriteListener.onWritePossible(WsHttpUpgradeHandler.java:243)
    at org.apache.catalina.core.StandardWrapperValve.async(StandardWrapperValve.java:605)
    at org.apache.catalina.core.StandardWrapperValve.event(StandardWrapperValve.java:350)
    at org.apache.catalina.core.StandardContextValve.event(StandardContextValve.java:171)
    at org.jboss.modcluster.container.jbossweb.JBossWebContext$RequestListenerValve.event(JBossWebContext.java:89)
    at org.apache.catalina.valves.ValveBase.event(ValveBase.java:185)
    at org.apache.catalina.core.StandardHostValve.event(StandardHostValve.java:253)
    at org.apache.catalina.valves.ValveBase.event(ValveBase.java:185)
    at org.apache.catalina.core.StandardEngineValve.event(StandardEngineValve.java:121)
    at org.apache.catalina.connector.CoyoteAdapter.event(CoyoteAdapter.java:227)
    at org.apache.coyote.http11.Http11NioProcessor.event(Http11NioProcessor.java:232)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.event(Http11NioProtocol.java:819)
    - locked <0x00000007916bfb58> (a org.apache.coyote.http11.Http11NioProcessor)
    at org.apache.tomcat.util.net.NioEndpoint$ChannelProcessor.run(NioEndpoint.java:940)
    - locked <0x0000000791ce7b78> (a java.lang.Object)
    at org.jboss.threads.SimpleDirectExecutor.execute(SimpleDirectExecutor.java:33)
    at org.jboss.threads.QueueExecutor.runTask(QueueExecutor.java:808)
    at org.jboss.threads.QueueExecutor.access$100(QueueExecutor.java:45)
    at org.jboss.threads.QueueExecutor$Worker.run(QueueExecutor.java:849)
    at java.lang.Thread.run(Thread.java:745)
    at org.jboss.threads.JBossThread.run(JBossThread.java:122)