Threads are blocked by 'DualStackPlainSocketImpl.waitForConnect'

[bomkang]

Hi, When the method 'DualStackPlainSocketImpl.waitForConnect' is running all the time, more and more threads('ldap.pool.Connections.get') will become blocked, and it will fill up all threads for a long time. If it is not released , it will cause Jira service hang up. Only when this method is finished can the block be released. Where is the timeout of socket connection set? Does this happen because timeout is set to null? 

Any advice would be appreciated!

Environment: Jira Data Centre 7.13, Windows Server 2012

User Directories: Microsoft Active Directory 

Directory configuration summary:

"ldap.connection.timeout": "30000"
"ldap.external.id": "objectGUID"
"ldap.filter.expiredUsers": "false"
"ldap.group.description": "description"
"ldap.group.dn": ""
"ldap.group.filter": "(objectCategory=noGroup)"
"ldap.group.name": "cn"
"ldap.group.objectclass": "group"
"ldap.group.usernames": "member"
"ldap.local.groups": "true"
"ldap.nestedgroups.disabled": "true"
"ldap.pagedresults": "true"
"ldap.pagedresults.size": "1000"
"ldap.password": ********
"ldap.pool.initsize": "null"
"ldap.pool.maxsize": "null"
"ldap.pool.prefsize": "null"
"ldap.pool.timeout": "0"
"ldap.propogate.changes": "false"
"ldap.read.timeout": "180000"
"ldap.referral": "true"
"ldap.relaxed.dn.standardisation": "true"
"ldap.roles.disabled": "true"
"ldap.search.timelimit": "60000"
"ldap.secure": "false"

Threads dump summary:

http-nio-80-exec-464	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-482	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.releasePooledConnection(Connections.java:219)
http-nio-80-exec-495	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-503	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-525	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-530	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-542	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-545	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-546	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-548	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-550	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-551	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-553	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-555	yes	5	RUNNABLERUNNABLE	java.lang.Thread.dumpThreads(Native Method)
http-nio-80-exec-556	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-557	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-559	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-561	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-562	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-568	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-569	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-571	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-573	yes	5	RUNNABLERUNNABLE	java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
http-nio-80-exec-579	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)
http-nio-80-exec-580	yes	5	BLOCKEDBLOCKED	com.sun.jndi.ldap.pool.Connections.get(Connections.java:139)