Issue #9653 has been updated by Hongbin Lu. Thanks again Eric. For reference, I posted the list of C extensions Gems I used. I am trying different versions of them to figure out where the error came from. therubyracer-0.12.1 yajl-ruby-1.2.0 passenger-3.0.21 mysql2-0.3.15 json-1.6.1 libxml-ruby-2.7.0 rails_admin-0.6.1 nokogiri-1.6.1 rdiscount-1.6.8 ---------------------------------------- Bug #9653: gc_sweep(): unknown data type 0x0 https://bugs.ruby-lang.org/issues/9653#change-45906 * Author: Hongbin Lu * Status: Open * Priority: Normal * Assignee: * Category: * Target version: * ruby -v: ruby 1.9.3p125 (2012-02-16 revision 34643) [x86_64-linux] * Backport: ---------------------------------------- The error message: /usr/local/lib/ruby/1.9.1/fileutils.rb:828: [BUG] gc_sweep(): unknown data type 0x0(0x54fd1e8) ruby 1.9.3p125 (2012-02-16 revision 34643) [x86_64-linux] This error is not deterministic. It occurred about 5% in my use case. Please find the full trace in the attached file, and feel free to let me know if further information is needed. ---Files-------------------------------- log.txt (339 KB) log-545.txt (309 KB) Gemfile.txt (782 Bytes) Gemfile.lock.txt (6.85 KB) -- https://bugs.ruby-lang.org/