From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?UTF-8?Q?Court=C3=A8s?=)
Subject: bug#27476: libguile/memoize.c is not thread safe,
	so syntax parameter expansion is not thread-safe
Date: Wed, 09 May 2018 11:23:59 +0200
Message-ID: <878t8tyyfk.fsf@gnu.org>
References: <87h8vvp1q7.fsf@elephly.net> <87377esu1a.fsf@gnu.org>
	<87k20nz18u.fsf@igalia.com> <87a81jj5gg.fsf@gnu.org>
	<87bmlyzxj7.fsf@elephly.net> <87shf44ny0.fsf@elephly.net>
	<878tfi9x15.fsf@gnu.org> <87h8nstms1.fsf@gnu.org>
	<874ljstlvq.fsf_-_@gnu.org> <87603x6x1f.fsf@igalia.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Return-path: <bug-guix-bounces+gcggb-bug-guix=m.gmane.org@gnu.org>
Received: from eggs.gnu.org ([2001:4830:134:3::10]:60719)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <Debian-debbugs@debbugs.gnu.org>) id 1fGLLK-0001jj-So
	for bug-guix@gnu.org; Wed, 09 May 2018 05:25:03 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <Debian-debbugs@debbugs.gnu.org>) id 1fGLLK-0001ZC-2t
	for bug-guix@gnu.org; Wed, 09 May 2018 05:25:02 -0400
Received: from debbugs.gnu.org ([208.118.235.43]:46919)
	by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16)
	(Exim 4.71) (envelope-from <Debian-debbugs@debbugs.gnu.org>)
	id 1fGLLJ-0001Z1-Vm
	for bug-guix@gnu.org; Wed, 09 May 2018 05:25:02 -0400
Sender: "Debbugs-submit" <debbugs-submit-bounces@debbugs.gnu.org>
Resent-Message-ID: <handler.27476.B27476.152585784919842@debbugs.gnu.org>
In-Reply-To: <87603x6x1f.fsf@igalia.com> (Andy Wingo's message of "Wed, 09 May
	2018 10:41:32 +0200")
List-Id: Bug reports for GNU Guix <bug-guix.gnu.org>
List-Unsubscribe: <https://lists.gnu.org/mailman/options/bug-guix>,
	<mailto:bug-guix-request@gnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/archive/html/bug-guix/>
List-Post: <mailto:bug-guix@gnu.org>
List-Help: <mailto:bug-guix-request@gnu.org?subject=help>
List-Subscribe: <https://lists.gnu.org/mailman/listinfo/bug-guix>,
	<mailto:bug-guix-request@gnu.org?subject=subscribe>
Errors-To: bug-guix-bounces+gcggb-bug-guix=m.gmane.org@gnu.org
Sender: "bug-Guix" <bug-guix-bounces+gcggb-bug-guix=m.gmane.org@gnu.org>
To: Andy Wingo <wingo@igalia.com>
Cc: 27476@debbugs.gnu.org

Hello Andy!

Andy Wingo <wingo@igalia.com> skribis:

> On Mon 30 Apr 2018 23:39, ludo@gnu.org (Ludovic Court=C3=A8s) writes:
>
>> So the problem, AIUI, is that psyntax evaluates syntax parameters using
>> =E2=80=98primitive-eval=E2=80=99 (via =E2=80=98eval-local-transformer=E2=
=80=99), but memoization in
>> (ice-9 eval) is not thread-safe, hence the random crashes.
>
> Sorry I've been a bit AWOL here... if this diagnosis is correct, then
> the problem is ultimately the memoization that needs to be thread-safe,
> right?

It looks like it, yes.

> Is the memoization you are referring to the "set!" in the "lazy" form in
> ice-9/eval.scm ?  Or something else?  FWIW I would not think the "set!"
> could be the issue, at least on x86, but who knows.

Actually I=E2=80=99m not sure exactly.  =E2=80=98memoize-expression=E2=80=
=99 itself is
side-effect-free, right?

Thanks for your feedback,
Ludo=E2=80=99.