Deadlock in AbstractAuthAuthority

Description

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I’m seeing a deadlock when using the AbstractAuthAuthority code. This seem to happen when there rapid requests to create a conference are being processed. Here is the out put of a thread dump (I can attach the full dump if that would help):

Found one Java-level deadlock:
=============================
"pool-7-thread-17":
  waiting to lock monitor 0x00007f1c780375a8 (object 0x000000070048bdf0, a java.lang.Object),
  which is held by "pool-7-thread-10"
"pool-7-thread-10":
  waiting to lock monitor 0x00007f1c78035ef8 (object 0x0000000782512f08, a java.util.HashMap),
  which is held by "Smack-Single Threaded Executor 0 (0)"
"Smack-Single Threaded Executor 0 (0)":
  waiting to lock monitor 0x00007f1c780375a8 (object 0x000000070048bdf0, a java.lang.Object),
  which is held by "pool-7-thread-10"

Java stack information for the threads listed above:
===================================================
"pool-7-thread-17":
	at org.jitsi.jicofo.auth.AbstractAuthAuthority.processAuthentication(AbstractAuthAuthority.java:347)
	- waiting to lock <0x000000070048bdf0> (a java.lang.Object)
	at org.jitsi.jicofo.xmpp.FocusComponent.processExtensions(FocusComponent.java:292)
	at org.jitsi.jicofo.xmpp.FocusComponent.handleConferenceIq(FocusComponent.java:343)
	at org.jitsi.jicofo.xmpp.FocusComponent.handleIQSetImpl(FocusComponent.java:221)
	at org.jitsi.xmpp.component.ComponentBase.handleIQSet(ComponentBase.java:362)
	at org.xmpp.component.AbstractComponent.processIQRequest(AbstractComponent.java:515)
	at org.xmpp.component.AbstractComponent.processIQ(AbstractComponent.java:289)
	at org.xmpp.component.AbstractComponent.processQueuedPacket(AbstractComponent.java:239)
	at org.xmpp.component.AbstractComponent.access$100(AbstractComponent.java:81)
	at org.xmpp.component.AbstractComponent$PacketProcessor.run(AbstractComponent.java:1051)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
"pool-7-thread-10":
	at org.jitsi.impl.protocol.xmpp.ChatRoomImpl.getMembers(ChatRoomImpl.java:597)
	- waiting to lock <0x0000000782512f08> (a java.util.HashMap)
	at org.jitsi.jicofo.ChatRoomRoleAndPresence.jidAuthenticated(ChatRoomRoleAndPresence.java:313)
	at org.jitsi.jicofo.auth.AbstractAuthAuthority.notifyUserAuthenticated(AbstractAuthAuthority.java:336)
	at org.jitsi.jicofo.auth.AbstractAuthAuthority.authenticateJidWithSession(AbstractAuthAuthority.java:413)
	at org.jitsi.jicofo.auth.XMPPDomainAuthAuthority.processAuthLocked(XMPPDomainAuthAuthority.java:98)
	at org.jitsi.jicofo.auth.AbstractAuthAuthority.processAuthentication(AbstractAuthAuthority.java:347)
	- locked <0x000000070048bdf0> (a java.lang.Object)
	at org.jitsi.jicofo.xmpp.FocusComponent.processExtensions(FocusComponent.java:292)
	at org.jitsi.jicofo.xmpp.FocusComponent.handleConferenceIq(FocusComponent.java:343)
	at org.jitsi.jicofo.xmpp.FocusComponent.handleIQSetImpl(FocusComponent.java:221)
	at org.jitsi.xmpp.component.ComponentBase.handleIQSet(ComponentBase.java:362)
	at org.xmpp.component.AbstractComponent.processIQRequest(AbstractComponent.java:515)
	at org.xmpp.component.AbstractComponent.processIQ(AbstractComponent.java:289)
	at org.xmpp.component.AbstractComponent.processQueuedPacket(AbstractComponent.java:239)
	at org.xmpp.component.AbstractComponent.access$100(AbstractComponent.java:81)
	at org.xmpp.component.AbstractComponent$PacketProcessor.run(AbstractComponent.java:1051)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
"Smack-Single Threaded Executor 0 (0)":
	at org.jitsi.jicofo.auth.AbstractAuthAuthority.findSessionForJabberId(AbstractAuthAuthority.java:226)
	- waiting to lock <0x000000070048bdf0> (a java.lang.Object)
	at org.jitsi.jicofo.auth.AbstractAuthAuthority.getSessionForJid(AbstractAuthAuthority.java:251)
	at org.jitsi.jicofo.ChatRoomRoleAndPresence.checkGrantOwnerToAuthUser(ChatRoomRoleAndPresence.java:294)
	at org.jitsi.jicofo.ChatRoomRoleAndPresence.memberPresenceChanged(ChatRoomRoleAndPresence.java:146)
	at org.jitsi.impl.protocol.xmpp.ChatRoomImpl.lambda$notifyMemberJoined$32(ChatRoomImpl.java:915)
	at org.jitsi.impl.protocol.xmpp.ChatRoomImpl$$Lambda$7/204059536.accept(Unknown Source)
	at java.util.concurrent.CopyOnWriteArrayList.forEach(CopyOnWriteArrayList.java:890)
	at org.jitsi.impl.protocol.xmpp.ChatRoomImpl.notifyMemberJoined(ChatRoomImpl.java:915)
	at org.jitsi.impl.protocol.xmpp.ChatRoomImpl.processOtherPresence(ChatRoomImpl.java:1198)
	- locked <0x0000000782512f08> (a java.util.HashMap)
	at org.jitsi.impl.protocol.xmpp.ChatRoomImpl.processPresence(ChatRoomImpl.java:1239)
	at org.jivesoftware.smackx.muc.MultiUserChat$3.processStanza(MultiUserChat.java:251)
	at org.jivesoftware.smack.AbstractXMPPConnection$5.run(AbstractXMPPConnection.java:1229)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

Found 1 deadlock.

Current behavior

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deadlock. And jicofo needs to be restarted.

Expected Behavior

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Possible Solution

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Steps to reproduce

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request create conference requests rapidly.

Environment details

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Using build 417 of jicofo

[paweldomas]

The Pr is in review and should be merged this week.

[paweldomas]

The fix is in the master.