diff --git a/parse.y b/parse.y
index e7f99d51aa..17a24e4aea 100644
--- a/parse.y
+++ b/parse.y
@@ -10825,6 +10825,7 @@ parser_mark(void *ptr)
     rb_gc_mark(parser->result);
     rb_gc_mark(parser->parsing_thread);
 #endif
+    rb_gc_mark(parser->debug_buffer);
 #ifdef YYMALLOC
     rb_gc_mark((VALUE)parser->heap);
 #endif
diff --git a/version.h b/version.h
index 9789b5c9b4..25db5dd08a 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.3.0"
 #define RUBY_RELEASE_DATE "2016-03-30"
-#define RUBY_PATCHLEVEL 62
+#define RUBY_PATCHLEVEL 63
 
 #define RUBY_RELEASE_YEAR 2016
 #define RUBY_RELEASE_MONTH 3