Shutdown or undeployment hangs in DistributableSessionManager.stop until HTTP requests finish processing

Issue

• In JBoss EAP 6, If application is in use(web connector threads are in process, http sessions active), we can not redeploy application. Thread dumps show it stalled in DistributableSessionManager.stop:

"ServerService Thread Pool -- 135" prio=6 tid=0x0000000045bfb000 nid=0x22ac waiting on condition [0x000000005e88e000]
   java.lang.Thread.State: WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x0000000404554f28> (a java.util.concurrent.Semaphore$FairSync)
    at java.util.concurrent.locks.LockSupport.park(Unknown Source)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(Unknown Source)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(Unknown Source)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(Unknown Source)
    at java.util.concurrent.Semaphore.acquire(Unknown Source)
    at org.jboss.as.web.session.DistributableSessionManager.stop(DistributableSessionManager.java:419)
    at org.apache.catalina.core.StandardContext.stop(StandardContext.java:3916)