[#42344] [ruby-trunk - Feature #5964][Open] Make Symbols an Alternate Syntax for Strings — Tom Wardrop <tom@...>

23 messages 2012/02/03

[#42443] [ruby-trunk - Bug #5985][Open] miniruby skews "make benchmark" results — Eric Wong <normalperson@...>

21 messages 2012/02/08

[#42444] [ruby-trunk - Bug #5986][Open] Segmentation Fault — Luis Matta <levmatta@...>

16 messages 2012/02/08

[#42471] [ruby-trunk - Feature #5995][Open] calling io_advise_internal() in read_all() — Masaki Matsushita <glass.saga@...>

20 messages 2012/02/10

[#42560] [ruby-trunk - Bug #6011][Open] ruby-1.9.3-p0/lib/webrick/utils.rb:184: [BUG] Segmentation fault — Vit Ondruch <v.ondruch@...>

12 messages 2012/02/13

[#42579] [ruby-trunk - Bug #6012][Open] Proc#source_location also return the column — Roger Pack <rogerpack2005@...>

14 messages 2012/02/14

[#42685] [ruby-trunk - Bug #6036][Open] Test failures in Fedora Rawhide/17 — Bohuslav Kabrda <bkabrda@...>

14 messages 2012/02/16

[#42697] [ruby-trunk - Bug #6040][Open] Transcoding test failure: Big5 to UTF8 not defined (MinGW) — Luis Lavena <luislavena@...>

10 messages 2012/02/16

[#42813] [ruby-trunk - Feature #6065][Open] Allow Bignum marshalling/unmarshalling from C API — Martin Bosslet <Martin.Bosslet@...>

22 messages 2012/02/23

[#42815] [ruby-trunk - Bug #6066][Open] Fix "control may reach end of non-void function" warnings for clang — Eric Hodel <[email protected]>

15 messages 2012/02/23

[#42857] [ruby-trunk - Feature #6074][Open] Allow alias arguments to have a comma — Thomas Sawyer <transfire@...>

20 messages 2012/02/24

[#42891] [ruby-trunk - Feature #6083][Open] Hide a Bignum definition — Koichi Sasada <redmine@...>

23 messages 2012/02/25

[#42906] [ruby-trunk - Bug #6085][Open] Treatment of Wrong Number of Arguments — Marc-Andre Lafortune <ruby-core@...>

14 messages 2012/02/25

[#42949] [ruby-trunk - Bug #6089][Open] Test suite fails with OpenSSL 1.0.1 — Vit Ondruch <v.ondruch@...>

13 messages 2012/02/26

[ruby-core:42666] [ruby-trunk - Bug #6030] Thread-local "leak" in rb_exec_recursive*

From: Charles Nutter <headius@...>
Date: 2012-02-15 18:49:10 UTC
List: ruby-core #42666
Issue #6030 has been updated by Charles Nutter.


I forgot to point out a couple things...

* By "leak" I mean this will hold references to data longer than it should. It's not a true leak in that it is bounded.

* It is bounded, but only by method names; recursive_list_access keys those thread-locals based on the current method name from the current frame, which means it will "leak" as many hash objects as there are unique methods utilizing rb_exec_recursive*.

From recursive_list_access:

...
	VALUE sym = ID2SYM(rb_frame_this_func());
...
	list = rb_hash_new();
	OBJ_UNTRUST(list);
	rb_hash_aset(hash, sym, list);

In JRuby, I fixed this by having rb_exec_recursive_outer clean up the thread-local upon completion, and I added recursive_list_operation (Ruby.java, recursiveListOperation) as a new "outermost" function to wrap our version of rb_exec_recursive. our rb_exec_recursive also gained an safeguard + error if it is called without being inside recursive_list_operation.

The commits are here:

https://github.com/jruby/jruby/commit/8f2ba4214eb070a83951aef1f143ebf6ebcecce4

https://github.com/jruby/jruby/commit/f7c1ffd93f34cef816168f36f5fe4f960a9ac2e2

It was a more severe problem for JRuby because the hash (a RubyHash) held references to the current JRuby instance, keeping it alive for as long as the thread was alive. Still a "leak", but a larger amount of bounded data held for too long.
----------------------------------------
Bug #6030: Thread-local "leak" in rb_exec_recursive*
https://bugs.ruby-lang.org/issues/6030

Author: Charles Nutter
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: 1.9.3 head


I believe there may be a "leak" in the rb_exec_recursive* functions in thread.c.

We have ported these methods for recursion detection in JRuby, and as in MRI they use a map inside a thread-local to track method name + object references. However, none of these method ever clean up the thread local when the recursive walk is complete.

The thread-local data is initialized in thread.c, recursive_list_access, around line 3819 (in 1.9.3 branch):

    if (NIL_P(hash) || TYPE(hash) != T_HASH) {
	hash = rb_hash_new();
	OBJ_UNTRUST(hash);
	rb_thread_local_aset(rb_thread_current(), recursive_key, hash);

As far as I can tell, this thread-local is never cleared, holding a hash reference for as long as the thread is alive.


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