Tomcat 6 NIO connector leaks memory after upgrading tomcat6-6.0.24-90 rpm package

Solution Verified - Updated

Environment

  • Red Hat Enterprise Linux 6
  • Tomcat 6.0.24-90

Issue

  • We recently updated to Tomcat 6.0.24-90. We use the NIO connector and now hit OOMEs. The heap dump shows org.apache.coyote.RequestInfo objects building up in the org.apache.coyote.RequestGroupInfo's processor list.

Resolution

  • Upgrade to tomcat6-6.0.24-94 or later to acquire the fix
  • If you can not upgrade to the above fixed packages:
    • Don't use NIO connectors on Tomcat 6.0.24-90. (Use Java BIO connector or APR connector instead.)
    • Downgrade to Tomcat 6.0.24-83 or before.

Root Cause

  • This content is not included.BZ-1268352
    • This issue was made worse by the fix from This content is not included.BZ-1031327
    • The NIO connector does not properly offer processors back to the recycledProcessors queue. Thus, the processors are not cleaned up from the org.apache.coyote.RequestGroupInfo's processors list, leading to an easy OOME as Tomcat keeps creating more and more processors as they are never recycled and indefinitely kept in the org.apache.coyote.RequestGroupInfo processors list.
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