3 files changed, 14 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog
index 8d18179a40..c10ca38196 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Nov  4 02:04:25 2010  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* cont.c (rb_fiber_resume): raise an "double resume" error when root
+	  fiber is going to be resumed.  [ruby-dev:42523]
+
 Wed Nov  3 14:17:18 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/ostruct.rb (OpenStruct#delete_field): also undefine
diff --git a/cont.c b/cont.c
index b0b3f41c7d..b0defcaeb7 100644
--- a/cont.c
+++ b/cont.c
@@ -1292,7 +1292,7 @@ rb_fiber_resume(VALUE fibval, int argc, VALUE *argv)
     rb_fiber_t *fib;
     GetFiberPtr(fibval, fib);
 
-    if (fib->prev != Qnil) {
+    if (fib->prev != Qnil || fib->cont.type == ROOT_FIBER_CONTEXT) {
 	rb_raise(rb_eFiberError, "double resume");
     }
 
diff --git a/test/ruby/test_fiber.rb b/test/ruby/test_fiber.rb
index edfe55a1d3..ec64f98229 100644
--- a/test/ruby/test_fiber.rb
+++ b/test/ruby/test_fiber.rb
@@ -189,5 +189,13 @@ class TestFiber < Test::Unit::TestCase
       f1.transfer
     }, '[ruby-dev:40833]'
   end
+
+  def test_resume_root_fiber
+    assert_raise(FiberError) do
+      Thread.new do
+        Fiber.current.resume
+      end.join
+    end
+  end
 end