messagesPendingMastership in AbstractOpenFlowSwitch is not threadsafe

2015-11-12 09:25:48,710 | WARN | nager-background | DeviceManager | 143 - org.onosproject.onos-core-net - 1.4.0.SNAPSHOT | Failed to handle MastershipEvent{time=2015-11-12T09:25:48.659, type=MASTER_CHANGED, subject=of:0000000000000191, roleInfo=RoleInfo{master=10.0.3.182, backups=[]}}
java.lang.NullPointerException
at org.onosproject.openflow.controller.driver.AbstractOpenFlowSwitch.sendMsg(AbstractOpenFlowSwitch.java:112)
at org.onosproject.openflow.controller.driver.AbstractOpenFlowSwitch.sendMsg(AbstractOpenFlowSwitch.java:102)
at org.onosproject.provider.of.device.impl.OpenFlowDeviceProvider.triggerProbe(OpenFlowDeviceProvider.java:245)
at org.onosproject.net.device.impl.DeviceManager.applyRoleAndProbe(DeviceManager.java:551)[143:org.onosproject.onos-core-net:1.4.0.SNAPSHOT]
at org.onosproject.net.device.impl.DeviceManager.reassertRole(DeviceManager.java:597)[143:org.onosproject.onos-core-net:1.4.0.SNAPSHOT]
at org.onosproject.net.device.impl.DeviceManager.handleMastershipEvent(DeviceManager.java:661)[143:org.onosproject.onos-core-net:1.4.0.SNAPSHOT]
at org.onosproject.net.device.impl.DeviceManager.access$1300(DeviceManager.java:90)[143:org.onosproject.onos-core-net:1.4.0.SNAPSHOT]
at org.onosproject.net.device.impl.DeviceManager$InternalMastershipListener.lambda$event$56(DeviceManager.java:674)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)[:1.8.0_60]
at java.util.concurrent.FutureTask.run(FutureTask.java:266)[:1.8.0_60]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)[:1.8.0_60]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)[:1.8.0_60]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)[:1.8.0_60]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)[:1.8.0_60]
at java.lang.Thread.run(Thread.java:745)[:1.8.0_60]