• QueueTaskDispatcher locks the queue
• ThrottleQueueTaskDispatcher invokes Jenkins.Instance().getAllItems() method, which has a security check for the each item
• Every dispatching attempt causes security check for all jobs in the system
• Due to big delays, so that dispatching almost blocks the queue and web interfaces

Workaround - use Hudson.getInstance().getItemMap(), which has not security checks

"Jenkins cron thread" prio=10 tid=0x0000000005d28000 nid=0x667b runnable [0x0000000041df4000]
java.lang.Thread.State: RUNNABLE
at com.michelin.cio.hudson.plugins.rolestrategy.RoleMap$2.perform(RoleMap.java:270)
at com.michelin.cio.hudson.plugins.rolestrategy.RoleMap$RoleWalker.walk(RoleMap.java:327)
at com.michelin.cio.hudson.plugins.rolestrategy.RoleMap$RoleWalker.<init>(RoleMap.java:316)
at com.michelin.cio.hudson.plugins.rolestrategy.RoleMap$2.<init>(RoleMap.java:268)
at com.michelin.cio.hudson.plugins.rolestrategy.RoleMap.getMatchingRoles(RoleMap.java:268)
at com.michelin.cio.hudson.plugins.rolestrategy.RoleMap.newMatchingRoleMap(RoleMap.java:224)
at com.michelin.cio.hudson.plugins.rolestrategy.RoleBasedAuthorizationStrategy.getACL(RoleBasedAuthorizationStrategy.java:111)
at com.michelin.cio.hudson.plugins.rolestrategy.RoleBasedAuthorizationStrategy.getACL(RoleBasedAuthorizationStrategy.java:128)
at com.michelin.cio.hudson.plugins.rolestrategy.RoleBasedAuthorizationStrategy.getACL(RoleBasedAuthorizationStrategy.java:123)
at hudson.model.Job.getACL(Job.java:1324)
at hudson.model.AbstractItem.hasPermission(AbstractItem.java:448)
at jenkins.model.Jenkins.getAllItems(Jenkins.java:1397)
at hudson.plugins.throttleconcurrents.ThrottleQueueTaskDispatcher.getCategoryProjects(ThrottleQueueTaskDispatcher.java:211)
at hudson.plugins.throttleconcurrents.ThrottleQueueTaskDispatcher.canRun(ThrottleQueueTaskDispatcher.java:121)
at hudson.plugins.throttleconcurrents.ThrottleQueueTaskDispatcher.canTake(ThrottleQueueTaskDispatcher.java:36)
at hudson.model.queue.QueueTaskDispatcher.canTake(QueueTaskDispatcher.java:101)
at hudson.model.Queue$JobOffer.canTake(Queue.java:254)
at hudson.model.Queue.maintain(Queue.java:1032)

• locked <0x00000006805417d8> (a hudson.model.Queue)
  at hudson.model.Queue$MaintainTask.doRun(Queue.java:1762)
  at hudson.triggers.SafeTimerTask.run(SafeTimerTask.java:54)
  at java.util.TimerThread.mainLoop(Timer.java:555)
  at java.util.TimerThread.run(Timer.java:505)