# Logstash 5.4.3 crash "interrupted waiting for mutex: null" in DNS resolver

**URL:** <https://discuss.elastic.co/t/logstash-5-4-3-crash-interrupted-waiting-for-mutex-null-in-dns-resolver/98858>\
**Category:** Logstash\
**Created:** [August 30, 2017, 1:41pm UTC](https://discuss.elastic.co/t/logstash-5-4-3-crash-interrupted-waiting-for-mutex-null-in-dns-resolver/98858 "2017-08-30T13:41:51Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Daniel314](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/daniel314/32/21668_2.png) [@Daniel314](https://discuss.elastic.co/u/Daniel314)\
**Post date:** [August 30, 2017, 1:41pm UTC](https://discuss.elastic.co/t/logstash-5-4-3-crash-interrupted-waiting-for-mutex-null-in-dns-resolver/98858/1 "2017-08-30T13:41:51Z")

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Hello,

This is the second "interrupted" issue that I've encountered with Logstash 5.4.3 that causes it to crash (see [other post](https://discuss.elastic.co/t/logstash-regexp-interrupted-error-s/98757) for that issue.

[2017-08-30T04:12:41,881][ERROR][logstash.pipeline] Exception in pipelineworker, the pipeline stopped processing new events, please check your filter configuration and restart Logstash.  
{"exception"=\>"interrupted waiting for mutex: null"  
"backtrace"=\>["org/jruby/ext/thread/Mutex.java:94:in `lock'" "org/jruby/ext/thread/Mutex.java:147:in`synchronize'"  
"/usr/share/logstash/vendor/jruby/lib/ruby/1.9/resolv.rb:190:in `lazy_initialize'" "/usr/share/logstash/vendor/jruby/lib/ruby/1.9/resolv.rb:268:in`each\_name'"  
"/usr/share/logstash/vendor/jruby/lib/ruby/1.9/resolv.rb:151:in `each\_name'"  
[...]

[2017-08-30T04:12:49,271][FATAL][logstash.runner] An unexpected error occurred!  
{:error=\>#\<ConcurrencyError: interrupted waiting for mutex: null\>  
:backtrace=\>["org/jruby/ext/thread/Mutex.java:94:in `lock'" "org/jruby/ext/thread/Mutex.java:147:in`synchronize'"  
"/usr/share/logstash/vendor/jruby/lib/ruby/1.9/resolv.rb:190:in `lazy_initialize'" "/usr/share/logstash/vendor/jruby/lib/ruby/1.9/resolv.rb:268:in`each\_name'"  
"/usr/share/logstash/vendor/jruby/lib/ruby/1.9/resolv.rb:151:in `each_name'" "org/jruby/RubyArray.java:1613:in`each'"  
"/usr/share/logstash/vendor/jruby/lib/ruby/1.9/resolv.rb:150:in `each_name'" "/usr/share/logstash/vendor/jruby/lib/ruby/1.9/resolv.rb:132:in`getname'"  
[...]

This is Logstash 5.4.3, using Elastic's docker image at [docker.elastic.co/logstash/logstash:5.4.3](http://docker.elastic.co/logstash/logstash:5.4.3)

I think something that may be tickling this issue is that my Logstash setup is reading from a Kafka "firehose" and is constantly falling behind, only processing about 30% of the data from Kafka (it's a test instance, so it's not critical to me that everything get processed), which means the Logstash instance stays very busy.

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**Author:** ![jetnet](https://avatars.discourse-cdn.com/v4/letter/j/a87d85/32.png) [@jetnet](https://discuss.elastic.co/u/jetnet)\
**Post date:** [September 8, 2017, 4:22pm UTC](https://discuss.elastic.co/t/logstash-5-4-3-crash-interrupted-waiting-for-mutex-null-in-dns-resolver/98858/2 "2017-09-08T16:22:53Z")

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The same issue with 5.5.2 !

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [October 6, 2017, 4:23pm UTC](https://discuss.elastic.co/t/logstash-5-4-3-crash-interrupted-waiting-for-mutex-null-in-dns-resolver/98858/3 "2017-10-06T16:23:18Z")

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