Backport #2367: memory leak of Class#dup

• Status: Closed
• Assignee: yugui (Yuki Sonoda)

[mame (Yusuke Endoh)]

=begin
遠藤です。

Class#dup がメモリリークするようです。
class C; end; loop { C.dup } で使用メモリが徐々に増えてきます。

object.c の init_copy と class.c の rb_mod_init_copy で RCLASS_IV_TBL を
二重に確保しているのと、古い RCLASS_M_TBL を解放していないことが原因の
ようです。

以下のパッチで直りますが、init_copy と rb_mod_init_copy の使い分けが良く
分からないので、正しいか分かりません。
変なことをしなければたぶん普通に動くと思うので (loop { C.dup } も変です
が) 、一旦コミットしようと思います。

diff --git a/class.c b/class.c
index a97494b..056e171 100644
--- a/class.c
+++ b/class.c
@@ -151,6 +151,9 @@ rb_mod_init_copy(VALUE clone, VALUE orig)
if (RCLASS_IV_TBL(orig)) {
ID id;

• if (RCLASS_IV_TBL(clone)) {

•  st_free_table(RCLASS_IV_TBL(clone));
  

• }
  RCLASS_IV_TBL(clone) = st_copy(RCLASS_IV_TBL(orig));
  CONST_ID(id, "classpath");
  st_delete(RCLASS_IV_TBL(clone), (st_data_t*)&id, 0);
  @@ -159,6 +162,11 @@ rb_mod_init_copy(VALUE clone, VALUE orig)
  }
  if (RCLASS_M_TBL(orig)) {
  struct clone_method_data data;
• if (RCLASS_M_TBL(clone)) {

•  extern void rb_free_m_table(st_table *tbl);
  

•  rb_free_m_table(RCLASS_M_TBL(clone));
  

• }
  data.tbl = RCLASS_M_TBL(clone) = st_init_numtable();
  data.klass = clone;
  st_foreach(RCLASS_M_TBL(orig), clone_method,
  diff --git a/gc.c b/gc.c
  index f472bfc..9de079b 100644
  --- a/gc.c
  +++ b/gc.c
  @@ -1459,8 +1459,8 @@ free_method_entry_i(ID key, rb_method_entry_t
  *me, st_data_t data)
  return ST_CONTINUE;
  }

-static void
-free_m_table(st_table *tbl)
+void
+rb_free_m_table(st_table *tbl)
{
st_foreach(tbl, free_method_entry_i, 0);
st_free_table(tbl);
@@ -1988,7 +1988,7 @@ obj_free(rb_objspace_t *objspace, VALUE obj)
case T_MODULE:
case T_CLASS:
rb_clear_cache_by_class((VALUE)obj);

• free_m_table(RCLASS_M_TBL(obj));

• rb_free_m_table(RCLASS_M_TBL(obj));
  if (RCLASS_IV_TBL(obj)) {
  st_free_table(RCLASS_IV_TBL(obj));
  }

--
Yusuke ENDOH [e-mail]
=end

[mame (Yusuke Endoh)]

• Status changed from Open to Closed
• % Done changed from 0 to 100

=begin
This issue was solved with changeset r25768.
Yusuke, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

=end

[nobu (Nobuyoshi Nakada)]

• Category set to core
• Status changed from Closed to Assigned
• Assignee set to yugui (Yuki Sonoda)

=begin

=end

[jeremyevans0 (Jeremy Evans)]

• Description updated (diff)
• Status changed from Assigned to Closed