We've seen several instances of these mystery deadlocks in impalad's embedded JVM. The signature is a deadlock stemming from sun.security.provider.Sun being locked by an unknown owner.
If this happens in HDFS, it causes HDFS I/O to hang and queries to get stuck. If it happens in the Kudu client it also causes hangs.
|Abort stuck impalad if JVM deadlock is detected||Resolved|