* cont.c (cont_init): clear macihne_stack_start/end of saved thread to

   prevent mark machine stack of GC'ed Thread. root Fiber is not initialized by
   fiber_init(). based on a patch by Serge Balyuk [ruby-core:35891] fixes #4612
 * test/ruby/test_fiber.rb (test_gc_root_fiber): add test for it.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@31577 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 11 insertions, 0 deletions

diff --git a/test/ruby/test_fiber.rb b/test/ruby/test_fiber.rb
index ec64f98229..e3e40566f8 100644
--- a/test/ruby/test_fiber.rb
+++ b/test/ruby/test_fiber.rb
@@ -197,5 +197,16 @@ class TestFiber < Test::Unit::TestCase
       end.join
     end
   end
+
+  def test_gc_root_fiber
+    bug4612 = '[ruby-core:35891]'
+
+    assert_normal_exit %q{
+      require 'fiber'
+      GC.stress = true
+      Thread.start{ Fiber.current; nil }.join
+      GC.start
+    }, bug4612
+  end
 end