From: redmine@mattbrictson.com
To: ruby-core@ruby-lang.org
Subject: [ruby-core:69198] [Ruby trunk - Bug #10871] Sclass thread unsafe due to CREF sharing
Date: Thu, 14 May 2015 18:18:25 +0000 [thread overview]
Message-ID: <redmine.journal-52453.20150514181801.0b3459db8be90ac1@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-10871.20150219215323@ruby-lang.org
Issue #10871 has been updated by Matt Brictson.
I recently opened bug #11153 which may be related. When using threads, methods defined inside `class << obj` sometimes fail to work. Feel free to close mine as a duplicate if it is the same underlying cause. In any case I would also appreciate a backport. :)
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Bug #10871: Sclass thread unsafe due to CREF sharing
https://bugs.ruby-lang.org/issues/10871#change-52453
* Author: Evan Phoenix
* Status: Open
* Priority: High
* Assignee:
* ruby -v: 2.2.0p0, trunk
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
When entering an sclass, the context is tracked via the same cref mechanism used for class and module, specifically on the iseq->cref_stack. The bug is that the cref_stack is the wrong place to put the new cref because the scope is specific only to that sclass body. Mutating and using the iseq->cref_stack causes any code that reads the cref via this cref_stack to incorrectly pick up the sclass instance instead of the proper scope!
This is major thread safety bug because it means that all uses of `class << obj` are thread-unsafe and can cause random code to fail.
Here is a simple reproduction of the bug: https://gist.github.com/evanphx/6eef92f2c40662a4171b
I attempted to fix the bug by treating an sclass body the same as an eval, which already has special handling for cref's but I don't understand the code enough to make that change quickly.
I believe this is a major bug and hope that ruby-core can address it soon.
Thank you!
--
https://bugs.ruby-lang.org/
next prev parent reply other threads:[~2015-05-14 18:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <redmine.issue-10871.20150219215323@ruby-lang.org>
2015-02-19 21:53 ` [ruby-core:68191] [Ruby trunk - Bug #10871] [Open] Sclass thread unsafe due to CREF sharing evan
2015-02-23 0:18 ` [ruby-core:68233] [Ruby trunk - Bug #10871] " tenderlove
2015-02-23 10:41 ` [ruby-core:68248] " ko1
2015-03-30 16:57 ` [ruby-core:68696] " clay
2015-03-30 19:27 ` [ruby-core:68697] " ko1
2015-04-27 21:34 ` [ruby-core:69003] " evan
2015-05-12 18:41 ` [ruby-core:69152] " wildgriffin45
2015-05-14 18:18 ` redmine [this message]
2015-06-16 8:45 ` [ruby-core:69602] " ko1
2015-06-16 9:23 ` [ruby-core:69603] " ko1
2015-06-17 21:11 ` [ruby-core:69636] " nagachika00
2015-06-17 23:16 ` [ruby-core:69640] " ko1
2015-06-30 18:55 ` [ruby-core:69818] " nagachika00
2015-07-11 20:43 ` [ruby-core:69948] " nagachika00
2015-08-24 16:26 ` [ruby-core:70574] " nagachika00
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