diff --git a/spec/ruby/core/file/birthtime_spec.rb b/spec/ruby/core/file/birthtime_spec.rb
index 315a4d2be3..cab749f7b4 100644
--- a/spec/ruby/core/file/birthtime_spec.rb
+++ b/spec/ruby/core/file/birthtime_spec.rb
@@ -50,9 +50,11 @@ describe "File#birthtime" do
     end
   end
 
-  platform_is :linux, :openbsd do
+  platform_is :openbsd do
     it "raises an NotImplementedError" do
       lambda { @file.birthtime }.should raise_error(NotImplementedError)
     end
   end
+
+  # TODO: depends on Linux kernel version
 end