From: Motohiro KOSAKI <kosaki.motohiro@...>
Date: 2011-09-12T02:27:18+09:00
Subject: [ruby-core:39475] [Ruby 1.9 - Bug #5306] Application Hangs Due to Recent rb_thread_select Changes


Issue #5306 has been updated by Motohiro KOSAKI.

File old_thread_select.patch added

> static void
> rb_fd_rcopy(fd_set *dst, rb_fdset_t *src)
> {
>     size_t size = howmany(rb_fd_max(src), NFDBITS) * sizeof(fd_mask);
>     if (size < sizeof(fd_set)) size = sizeof(fd_set);
>     memcpy(dst, rb_fd_ptr(src), size);
> }

If size > sizeof(fd_set), this code makes memory corruption.


> static void
> rb_fd_rcopy(fd_set *dst, rb_fdset_t *src)
> {
> 	memcpy(dst->fd_array, src->fdset->fd_array,
>	       dst->fd_count * sizeof(dst->fd_array[0]);
>	dst->fd_count = src->fdset->fd_count;
> }

Bad indentation of coding style violation.
Also, if src->fdset->fd_count > FD_SETSIZE, we should return an error or raise an exception.

Attached new patch. It works both linux and windows. Can you please review it?








----------------------------------------
Bug #5306: Application Hangs Due to Recent rb_thread_select Changes
http://redmine.ruby-lang.org/issues/5306

Author: Charlie Savage
Status: Open
Priority: High
Assignee: 
Category: core
Target version: 1.9.3
ruby -v: -


This commit:

4e9438bc9153f7a1f4ea0af85c8dbe359e1a55d8

Changed the implementation of rb_thread_select.  

It causes eventmachine to hang on CentOS 5.5.  Not sure what the issue is, but its easily reproduced by by running the test eventmachine/tests/test_epoll.rb.  

We noticed this because it also causes the tweetstream gem to hang.

The same setup works on Fedora 14 and an up-to-date arch linux.  Specific version information included below.

We temporarily fixed this by reverting the commit.

Since Centos is a common production environment (and the one we are using), this seems to us a blocker for 1.9.3. 

We are happy to provide any additional information or test fixes.  

Thanks - Charlie

--------------
We are running this version of CentOS:

Linux app1.zerista.com 2.6.18-238.19.1.el5.centos.plus #1 SMP Mon Jul 18 10:05:09 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux

And this version of Fedora:

Linux ammonite.internal.zerista.com 2.6.35.14-95.fc14.x86_64 #1 SMP Tue Aug 16 21:01:58 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

And this version of eventmachine:

eventmachine (1.0.0.beta.3)

And this version of tweetstream:

tweetstream (1.0.4)


-- 
http://redmine.ruby-lang.org