From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 9228 invoked by alias); 12 May 2014 08:00:31 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 9206 invoked by uid 89); 12 May 2014 08:00:30 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.4 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_SOFTFAIL autolearn=no version=3.3.2 X-HELO: hera.aquilenet.fr Received: from hera.aquilenet.fr (HELO hera.aquilenet.fr) (141.255.128.1) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 12 May 2014 08:00:27 +0000 Received: from localhost (localhost [127.0.0.1]) by hera.aquilenet.fr (Postfix) with ESMTP id E7C2B287A; Mon, 12 May 2014 10:00:22 +0200 (CEST) Received: from hera.aquilenet.fr ([127.0.0.1]) by localhost (hera.aquilenet.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id U4dh0NDJptEK; Mon, 12 May 2014 10:00:22 +0200 (CEST) Received: from pluto (pluto.bordeaux.inria.fr [193.50.110.57]) by hera.aquilenet.fr (Postfix) with ESMTPSA id 9C2D6F32; Mon, 12 May 2014 10:00:22 +0200 (CEST) From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=) To: Doug Evans Cc: Eli Zaretskii , Tillmann Karras , "gdb-patches\@sourceware.org" , Andy Wingo Subject: GDB-Guile vs. libgc 7.4 marker threads References: <83ha54zrry.fsf@gnu.org> X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 23 =?utf-8?Q?Flor=C3=A9al?= an 222 de la =?utf-8?Q?R?= =?utf-8?Q?=C3=A9volution?= X-PGP-Key-ID: 0xEA52ECF4 X-PGP-Key: http://www.fdn.fr/~lcourtes/ludovic.asc X-PGP-Fingerprint: 83C4 F8E5 10A3 3B4C 5BEA D15D 77DD 95E2 EA52 ECF4 X-OS: x86_64-unknown-linux-gnu Date: Mon, 12 May 2014 08:00:00 -0000 In-Reply-To: (Doug Evans's message of "Sun, 11 May 2014 20:24:55 -0700") Message-ID: <87wqdr1l61.fsf_-_@gnu.org> User-Agent: Gnus/5.130009 (Ma Gnus v0.9) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-SW-Source: 2014-05/txt/msg00132.txt.bz2 [+ Andy :-)] Doug Evans skribis: > On Sun, May 4, 2014 at 11:03 PM, Eli Zaretskii wrote: >>> Date: Sun, 04 May 2014 21:59:08 +0200 >>> From: Tillmann Karras >>> Cc: gdb-patches@sourceware.org >>> >>> On 2014-04-28 00:15, Doug Evans wrote: >>> > If you're running gdb under gdb, and the child gdb is hanging, >>> > can you type Ctrl-C when it hangs, and then obtain a backtrace of the >>> > child gdb? >>> >>> Pressing Ctrl-C just prints "[New Thread 0x7ffff4b6f700 (LWP 14601)]" >>> but I don't get any prompt. >> >> My crystal ball says that Ctrl-C causes Guile to start its signal >> delivery thread, which is the reason for the "New Thread" message you >> see. >> >>> > It's been suggested to give the following a try. >>> > Does that fix things for you? >>> > >>> > bash$ export GC_MARKERS=3D1 >>> > >>> > before starting gdb >>> > It's a workaround for a libgc 7.4.0 bug. >>> > I verified my arch-linux has libgc 7.4.0, but I may have just gotten >>> > lucky. >>> >>> Yes, "gdb -ex 'set environment GC_MARKERS 1' -ex r gdb" makes it work >>> for me. (Maybe your test VM had only one core?) >> >> What bug is that in libgc, and what are its symptoms? > > A google search for libgc 7.4 GC_MARKERS found this: > > https://lists.gnu.org/archive/html/guile-commits/2014-04/msg00051.html Yes, but note that this commit is for Guile 2.2. That said, although Guile 2.0 builds and runs fine with 7.4, I noticed that GDB-Guile is confused when there are several marker threads. Thus, we have to set GC_MARKERS=3D1 when running Guile-GDB with Guile 2.0 on libgc 7.4. Probably the GC_MARKERS hack linked above should be applied to GDB as well. WDYT? Thanks, Ludo=E2=80=99.