Automatic Server Hang Bug Diagnosis: Feasible Reality or Pipe Dream?

It is notoriously difficult to diagnose server hang bugs as they often generate little diagnostic information and are difficult to reproduce offline. In this paper, we present a characteristic study of 177 real software hang bugs from 8 common open source server systems (i.e., Apache, Lighttpd, My SQL, Squid, HDFS, Hadoop Mapreduce, Tomcat, Cassandra). We identify three major root cause categories (i.e., Programmer errors, mishandled values, concurrency issues). We then describe two major problems (i.e., False positives and false negatives) while applying existing rule-based bug detection techniques to those bugs.