Exception in thread "LogStash::Runner" org.jruby.exceptions.RaiseException

[lijie123bes]

Exception in thread "LogStash::Runner" org.jruby.exceptions.RaiseException: (InvalidByteSequenceError) ""\xD8"" on US-ASCII
    at org.jruby.RubyString.encode(org/jruby/RubyString.java:7596)
    at json.ext.GeneratorMethods$RbHash.to_json(json/ext/GeneratorMethods.java:71)
    at LogStash::Event.to_json(file:/maverik/software/logstash/logstash-1.2.2-flatjar.jar!/logstash/event.rb:156)
    at LogStash::Outputs::Redis.receive(file:/maverik/software/logstash/logstash-1.2.2-flatjar.jar!/logstash/outputs/redis.rb:150)
    at LogStash::Outputs::Base.handle(file:/maverik/software/logstash/logstash-1.2.2-flatjar.jar!/logstash/outputs/base.rb:85)
    at RUBY.initialize((eval):250)
    at org.jruby.RubyProc.call(org/jruby/RubyProc.java:271)
    at LogStash::Pipeline.output(file:/maverik/software/logstash/logstash-1.2.2-flatjar.jar!/logstash/pipeline.rb:254)
    at RUBY.outputworker(file:/maverik/software/logstash/logstash-1.2.2-flatjar.jar!/logstash/pipeline.rb:213)
    at RUBY.start_outputs(file:/maverik/software/logstash/logstash-1.2.2-flatjar.jar!/logstash/pipeline.rb:140)

here is my config

input
{
udp { type => "firewalls" port => "50006" codec => plain }
}
filter
{
grok    { match => [ "host", "%{IPORHOST:ipaddr}(:%{NUMBER})?" ] }
mutate  { replace => [ "fqdn", "%{ipaddr}" ] }
dns     { reverse => [ "fqdn", "fqdn" ] action => "replace" }
if [type] == "firewalls" { clone { clones => "firewalls.log" add_tag => "savetofile" } }
}
output
{
    #stdout { debug => true }
    #stdout { codec => rubydebug }
    redis   { host => "666.666.666.666" data_type => "list" key => "logstash" }
}