gistfile1.txt

diff --git a/lib/handler/mruby.c b/lib/handler/mruby.c
index d7f6266..0a1ceb6 100644
--- a/lib/handler/mruby.c
+++ b/lib/handler/mruby.c
@@ -660,6 +660,8 @@ static void send_response(h2o_mruby_generator_t *generator, mrb_int status, mrb_
         return;
     }
 
+    mrb_gc_arena_restore(mrb, gc_arena);
+
     /* send the entire response immediately */
     if (h2o_memis(generator->req->input.method.base, generator->req->input.method.len, H2O_STRLIT("HEAD"))) {
         h2o_start_response(generator->req, &generator->super);