From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 12740 invoked by alias); 30 Aug 2012 16:09:04 -0000 Received: (qmail 12724 invoked by uid 22791); 30 Aug 2012 16:09:02 -0000 X-SWARE-Spam-Status: No, hits=-3.5 required=5.0 tests=AWL,BAYES_00,KHOP_THREADED,RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from server-nat-6.cs.umd.edu (HELO bacon.cs.umd.edu) (128.8.127.149) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 30 Aug 2012 16:08:46 +0000 Received: from wireless-206-196-164-53.umd.edu (wireless-206-196-164-53.umd.edu [206.196.164.53]) (Authenticated sender: khooyp) by bacon.cs.umd.edu (Postfix) with ESMTPSA id D9355B40228; Thu, 30 Aug 2012 12:08:41 -0400 (EDT) Subject: Re: Disable -lmcheck when Python has threads (Re: [BUG] gdb crash when "python import gtk") Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: text/plain; charset=us-ascii From: Khoo Yit Phang In-Reply-To: <20120830160438.GA25469@host2.jankratochvil.net> Date: Thu, 30 Aug 2012 16:09:00 -0000 Cc: Khoo Yit Phang , Hui Zhu , gdb@sourceware.org Content-Transfer-Encoding: quoted-printable Message-Id: <41429A68-82EE-4B57-BAB3-559D2907A71B@cs.umd.edu> References: <20120719073959.GA10044@host2.jankratochvil.net> <20120830160438.GA25469@host2.jankratochvil.net> To: Jan Kratochvil X-CSD-MailScanner-ID: D9355B40228.A7A0F X-CSD-MailScanner: Found to be clean X-CSD-MailScanner-SpamCheck: not spam, SpamAssassin (not cached, score=-50, required 5, autolearn=not spam, ALL_TRUSTED -50.00) X-CSD-MailScanner-From: khooyp@cs.umd.edu X-CSD-MailScanner-Watermark: 1346947722.02082@IFeSAWgRvZ4cdbC85KHoXw Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2012-08/txt/msg00097.txt.bz2 Hi, On Aug 30, 2012, at 12:04 PM, Jan Kratochvil wrote: > Hi, >=20 > On Thu, 30 Aug 2012 18:00:46 +0200, Khoo Yit Phang wrote: >> I ran into a similar issue as below and tracked it down: the "memory >> clobbered before allocated block" (and other related messages) because >> -lmcheck is not thread safe, and triggers spuriously when threads are us= ed >> in Python (e.g., the "gtk" module). >=20 > this needs some references to glibc/gtk/python maintainers statements etc. >=20 > -lmcheck is AFAIK thread safe in glibc itself. -lmcheck is definitely not thread safe, at least as of glibc 2.13 (Ubuntu 1= 1.04). See the first answer of http://stackoverflow.com/questions/314931/gl= ibcs-lmcheck-option-and-multithreading. Yit August 30, 2012