* 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

ChangeLog

@@ -1,3 +1,10 @@
+Sun May 15 21:22:35 2011  CHIKANAGA Tomoyuki  <nagachika00@gmail.com>
+
+	* 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.
+
 Sun May 15 21:04:29 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* transcode.c (econv_init): revert r31353.  [ruby-dev:43512]

cont.c

@@ -383,6 +383,7 @@ cont_init(rb_context_t *cont, rb_thread_t *th)
     /* save thread context */
     cont->saved_thread = *th;
     cont->saved_thread.local_storage = 0;
+    cont->saved_thread.machine_stack_start = cont->saved_thread.machine_stack_end = 0;
 }
 
 static rb_context_t *

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