X-Recipient: archive-cygwin AT delorie DOT com
X-SWARE-Spam-Status: No, hits=-2.2 required=5.0	tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,T_TO_NO_BRKTS_FREEMAIL
X-Spam-Check-By: sourceware.org
Message-ID: <4BE06C6B.1020502@gmail.com>
Date: Tue, 04 May 2010 19:50:19 +0100
From: Dave Korn <dave DOT korn DOT cygwin AT googlemail DOT com>
User-Agent: Thunderbird 2.0.0.17 (Windows/20080914)
MIME-Version: 1.0
To: cygwin AT cygwin DOT com
Subject: Re: 1.7.5-1: fork throw segfault with g++ 4.3.4
References: <118687966886207198029573800488537596901-Webmail AT me DOT com>
In-Reply-To: <118687966886207198029573800488537596901-Webmail@me.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id: <cygwin.cygwin.com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com

On 27/04/2010 08:02, Tim Wilson-Brown wrote:
> Hi,
> 
> I have identified a reproducible segfault when throwing exceptions in the
> thrift IPC library under cygwin 1.7.5-1.

  Thanks for the simple testcase :)

  I have debugged what is happening, and it appears that the typeinfo for the
stringexcept class is getting corrupted in the child process, apparently
because a pseudo-reloc is being applied twice.  I will debug this further
shortly and figure out a fix; it also appears that the problem will be masked
in the upcoming gcc-4.5.0 release (as a side-effect of the fact that the new
libstdc++ dll will export typeinfos directly, rather than leaving them as
static objects in the libstdc++ import library as is the practice in the 4.3.4
release; this avoids needing a pseudo-reloc, apparently, but the bug would
presumably still turn up in other circumstances.)

    cheers,
      DaveK




--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple