From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#41321: 27.0.91; Emacs aborts due to invalid pseudovector objects Date: Sat, 30 May 2020 08:50:18 +0300 Message-ID: <83imgem0o5.fsf@gnu.org> References: <83zha8cgpi.fsf@gnu.org> <83imgublku.fsf@gnu.org> <831rncjuwf.fsf@gnu.org> <83h7w5xvfa.fsf@gnu.org> <83y2phwb9x.fsf@gnu.org> <83r1v9w9vi.fsf@gnu.org> <83mu5xw50d.fsf@gnu.org> <83k110wxte.fsf@gnu.org> <4bab5f55-95fe-cf34-e490-1d4319728395@cs.ucla.edu> <837dwyvi74.fsf@gnu.org> <1484f569-c260-9fb0-bfe1-67897de289d3@cs.ucla.edu> <83blm9tn4j.fsf@gnu.org> <4aeb8963-4fd1-fcd4-e6e1-be409ab54775@cs.ucla.edu> <83tuzzrk30.fsf@gnu.org> <749bc7d0-6376-ec2e-7f84-dcd3a3cea465@cs.ucla.edu> <83sgfjqn49.fsf@gnu.org> Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="129601"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 41321@debbugs.gnu.org, monnier@iro.umontreal.ca, pipcet@gmail.com To: Paul Eggert Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sat May 30 07:51:10 2020 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jeuOk-000Xbw-79 for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 30 May 2020 07:51:10 +0200 Original-Received: from localhost ([::1]:45564 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jeuOj-0001Qo-8V for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 30 May 2020 01:51:09 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54754) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jeuOc-0001OU-9F for bug-gnu-emacs@gnu.org; Sat, 30 May 2020 01:51:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:45235) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jeuOb-000274-UC for bug-gnu-emacs@gnu.org; Sat, 30 May 2020 01:51:01 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jeuOb-0005A3-TF for bug-gnu-emacs@gnu.org; Sat, 30 May 2020 01:51:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sat, 30 May 2020 05:51:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 41321 X-GNU-PR-Package: emacs Original-Received: via spool by 41321-submit@debbugs.gnu.org id=B41321.159081784519816 (code B ref 41321); Sat, 30 May 2020 05:51:01 +0000 Original-Received: (at 41321) by debbugs.gnu.org; 30 May 2020 05:50:45 +0000 Original-Received: from localhost ([127.0.0.1]:56781 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jeuO8-00059M-RU for submit@debbugs.gnu.org; Sat, 30 May 2020 01:50:45 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:47290) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jeuO7-000598-0i for 41321@debbugs.gnu.org; Sat, 30 May 2020 01:50:31 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:56716) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jeuO0-0001Wj-5n; Sat, 30 May 2020 01:50:24 -0400 Original-Received: from [176.228.60.248] (port=2722 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1jeuNz-0000dp-C8; Sat, 30 May 2020 01:50:23 -0400 In-Reply-To: (message from Paul Eggert on Fri, 29 May 2020 13:24:55 -0700) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:181213 Archived-At: > Cc: pipcet@gmail.com, 41321@debbugs.gnu.org, monnier@iro.umontreal.ca > From: Paul Eggert > Date: Fri, 29 May 2020 13:24:55 -0700 > > There are really two bugs here. > > 1. The idea of taking the address modulo LISP_ALIGNMENT is wrong, as a pointer > can point into the middle of (say) a pseudovector and not be > LISP_ALIGNMENT-aligned. Replacing LISP_ALIGNMENT with GCALIGNMENT does not fix > this bug in general, because such a pointer might not be GCALIGNMENT-aligned > either. This bug can cause crashes because it causes GC to think an object is > garbage when it's not garbage. > > 2. LISP_ALIGNMENT is too large on MinGW and some other platforms. > > The patch I sent earlier attempted to be the simplest patch that would fix the > bug you observed on MinGW, which is a special case of (1). It does not attempt > to fix all plausible cases of (1), nor does it address (2). > > We can fix these two bugs separately, by installing the attached patches into > emacs-27. The first patch fixes (1) and thus fixes the crash along with other > plausible crashes. The second one fixes (2), and this fixes the MinGW crash in a > different way but does not fix the crash on other plausible platforms. (1) > probably has better performance than (2), though I doubt whether users will notice. Since (1) is for now purely theoretical (and rare even in that theoretical case), I'd like to see (2) applied to emacs-27. Let's do that soon, as I'd like to have another pretest in the near future. Thanks.