nokogiri + libxml memory corruption

crashy.rb

# This segfault was tested on Ubuntu Precise, With Ruby 2.1.6 and 2.2.2.
# It does _not_ crash on OS X Yosemite.

gem 'nokogiri', '1.6.6.2'
gem 'libxml-ruby', '2.8.0'

require 'nokogiri'
require 'libxml' # comment out this line, and no crash

message = "<h2>BOOM!</h2>"

20_000.times do
  # GC.disable # disabling GC during the Nokogiri calls will prevent the crash
  node = Nokogiri::HTML::DocumentFragment.parse(message)
  node.add_previous_sibling(Nokogiri::XML::Text.new(' ', node.document))
  node.add_next_sibling(Nokogiri::XML::Text.new(' ', node.document))
  # GC.enable
end