From: nobu@...
Date: 2014-11-25T12:02:41+00:00
Subject: [ruby-core:66457] [ruby-trunk - Bug #10537] Repeated creation and garbage collection of WeakRef instances against a single object leaks memory

Issue #10537 has been updated by Nobuyoshi Nakada.

Description updated

I can't reproduce the error, too.

What about this patch?

~~~diff
diff --git a/gc.c b/gc.c
index 9c0dbef..f4c4e93 100644
--- a/gc.c
+++ b/gc.c
@@ -7869,10 +7869,10 @@ wmap_aset(VALUE self, VALUE wmap, VALUE orig)
     TypedData_Get_Struct(self, struct weakmap, &weakmap_type, w);
     should_be_finalizable(orig);
     should_be_finalizable(wmap);
-    define_final0(orig, w->final);
-    define_final0(wmap, w->final);
-    st_update(w->obj2wmap, (st_data_t)orig, wmap_aset_update, wmap);
-    st_insert(w->wmap2obj, (st_data_t)wmap, (st_data_t)orig);
+    if (!st_update(w->obj2wmap, (st_data_t)orig, wmap_aset_update, wmap))
+	define_final0(orig, w->final);
+    if (!st_insert(w->wmap2obj, (st_data_t)wmap, (st_data_t)orig))
+	define_final0(wmap, w->final);
     return nonspecial_obj_id(orig);
 }
 


----------------------------------------
Bug #10537: Repeated creation and garbage collection of WeakRef instances against a single object leaks memory
https://bugs.ruby-lang.org/issues/10537#change-50080

* Author: Alex Boyd
* Status: Open
* Priority: Normal
* Assignee: 
* Category: lib
* Target version: 
* ruby -v: ruby 2.2.0dev (2014-11-24 trunk 48552) [x86_64-darwin14]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
~~~ruby
require 'weakref'
a = Object.new
1_000_000.times do
  WeakRef.new a
end
GC.start
~~~

The above results in Ruby consuming ~150 MB of RAM, all of which can only be freed by dropping `a`. This should not be the case - an object being weakly referenced should not itself hold a reference to the WeakRef (or any associated data) pointing at it.



-- 
https://bugs.ruby-lang.org/