diff --git a/ChangeLog b/ChangeLog
index e4e3ef9121..27f309b8a1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Jan 24 21:04:45 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* error.c (rb_invalid_str): prevent intermediate variable from GC.
+	  [ruby-core:34820]
+
 Sun Jan 23 23:01:54 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* test/io/console/test_io_console.rb: Don't run test if the system
diff --git a/error.c b/error.c
index 217740f9d9..ca563722ba 100644
--- a/error.c
+++ b/error.c
@@ -970,7 +970,7 @@ nometh_err_args(VALUE self)
 void
 rb_invalid_str(const char *str, const char *type)
 {
-    VALUE s = rb_str_inspect(rb_str_new2(str));
+    volatile VALUE s = rb_str_inspect(rb_str_new2(str));
 
     rb_raise(rb_eArgError, "invalid value for %s: %s", type, RSTRING_PTR(s));
 }
diff --git a/test/ruby/test_float.rb b/test/ruby/test_float.rb
index 7ab4ffc649..85faf63355 100644
--- a/test/ruby/test_float.rb
+++ b/test/ruby/test_float.rb
@@ -472,6 +472,11 @@ class TestFloat < Test::Unit::TestCase
     assert(Float(o).nan?)
   end
 
+  def test_invalid_str
+    bug4310 = '[ruby-core:34820]'
+    assert_raise(ArgumentError, bug4310) {under_gc_stress {Float('a'*10000)}}
+  end
+
   def test_num2dbl
     assert_raise(TypeError) do
       1.0.step(2.0, "0.5") {}