rb_gc_impl_define_finalizer: unlock on early return

gc/default/default.c

@@ -2847,6 +2847,7 @@ rb_gc_impl_define_finalizer(void *objspace_ptr, VALUE obj, VALUE block)
             for (i = 0; i < len; i++) {
                 VALUE recv = RARRAY_AREF(table, i);
                 if (rb_equal(recv, block)) {
+                    rb_gc_vm_unlock(lev);
                     return recv;
                 }
             }

gc/mmtk/mmtk.c

@@ -986,6 +986,7 @@ rb_gc_impl_define_finalizer(void *objspace_ptr, VALUE obj, VALUE block)
             for (i = 0; i < len; i++) {
                 VALUE recv = RARRAY_AREF(table, i);
                 if (rb_equal(recv, block)) {
+                    rb_gc_vm_unlock(lev);
                     return recv;
                 }
             }

test2.rb

@@ -0,0 +1,2 @@
+ObjectSpace._id2ref(8) rescue nil
+

test3.rb

@@ -0,0 +1,12 @@
+ractors = 5.times.map do |i|
+  Ractor.new do
+    100_000.times.map do
+      o = Object.new
+      ObjectSpace.define_finalizer(o, ->(id) {})
+      o
+    end
+  end
+end
+
+ractors.each(&:take)
+