LogStash::Json::GeneratorError: Cannot serialize instance of: IOError

I have used the option --log-in-json with version 2.4.0 and received the following error (Logstash crashes):

LogStash::Json::GeneratorError: Cannot serialize instance of: IOError
jruby_dump at /opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.4.0-java/lib/logstash/json.rb:53
jruby_dump at /opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.4.0-java/lib/logstash/json.rb:50
<< at /opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.4.0-java/lib/logstash/logging/json.rb:15
<< at /opt/logstash/vendor/bundle/jruby/1.9/gems/cabin-0.8.1/lib/cabin/subscriber.rb:10
publish at /opt/logstash/vendor/bundle/jruby/1.9/gems/cabin-0.8.1/lib/cabin/channel.rb:196
each at org/jruby/RubyHash.java:1342
publish at /opt/logstash/vendor/bundle/jruby/1.9/gems/cabin-0.8.1/lib/cabin/channel.rb:193
synchronize at org/jruby/ext/thread/Mutex.java:149
publish at /opt/logstash/vendor/bundle/jruby/1.9/gems/cabin-0.8.1/lib/cabin/channel.rb:192
_log at /opt/logstash/vendor/bundle/jruby/1.9/gems/cabin-0.8.1/lib/cabin/mixins/logger.rb:113
log_with_level at /opt/logstash/vendor/bundle/jruby/1.9/gems/cabin-0.8.1/lib/cabin/mixins/logger.rb:90
error at /opt/logstash/vendor/bundle/jruby/1.9/gems/cabin-0.8.1/lib/cabin/mixins/logger.rb:75
filter_batch at /opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.4.0-java/lib/logstash/pipeline.rb:279
filter_batch at /opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.4.0-java/lib/logstash/pipeline.rb:265
worker_loop at /opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.4.0-java/lib/logstash/pipeline.rb:223
start_workers at /opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.4.0-java/lib/logstash/pipeline.rb:201