From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Lars Ingebrigtsen Newsgroups: gmane.emacs.bugs Subject: bug#7496: 23.2; copy recursive keymap cause crash Date: Sun, 13 Oct 2019 03:15:17 +0200 Message-ID: <874l0dh2e2.fsf@gnus.org> References: <871v67o9ns.fsf@nagi.lyrical.homelinux.net> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="152973"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) Cc: ARISAWA Akihiro , 7496@debbugs.gnu.org To: Stefan Monnier Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sun Oct 13 03:16:11 2019 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iJSUU-000dXy-KW for geb-bug-gnu-emacs@m.gmane.org; Sun, 13 Oct 2019 03:16:10 +0200 Original-Received: from localhost ([::1]:37036 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iJSUT-00025Y-Gl for geb-bug-gnu-emacs@m.gmane.org; Sat, 12 Oct 2019 21:16:09 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54378) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iJSUN-000257-Hk for bug-gnu-emacs@gnu.org; Sat, 12 Oct 2019 21:16:04 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iJSUM-0001d0-Al for bug-gnu-emacs@gnu.org; Sat, 12 Oct 2019 21:16:03 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:53945) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1iJSUM-0001cw-7c for bug-gnu-emacs@gnu.org; Sat, 12 Oct 2019 21:16:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1iJSUM-00047B-0l for bug-gnu-emacs@gnu.org; Sat, 12 Oct 2019 21:16:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Lars Ingebrigtsen Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 13 Oct 2019 01:16:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 7496 X-GNU-PR-Package: emacs Original-Received: via spool by 7496-submit@debbugs.gnu.org id=B7496.157092932715758 (code B ref 7496); Sun, 13 Oct 2019 01:16:01 +0000 Original-Received: (at 7496) by debbugs.gnu.org; 13 Oct 2019 01:15:27 +0000 Original-Received: from localhost ([127.0.0.1]:34530 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1iJSTn-000466-0Q for submit@debbugs.gnu.org; Sat, 12 Oct 2019 21:15:27 -0400 Original-Received: from quimby.gnus.org ([80.91.231.51]:44344) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1iJSTk-00045u-G2 for 7496@debbugs.gnu.org; Sat, 12 Oct 2019 21:15:25 -0400 Original-Received: from cm-84.212.202.86.getinternet.no ([84.212.202.86] helo=marnie) by quimby.gnus.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iJSTe-0002NI-8y; Sun, 13 Oct 2019 03:15:20 +0200 In-Reply-To: (Stefan Monnier's message of "Fri, 26 Nov 2010 22:01:28 -0500") X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.51.188.43 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.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:169076 Archived-At: Stefan Monnier writes: >> When I call `copy-keymap' with a keymap which contains recursive binding, >> the emacs crashed. >> I can reproduce it by following sexp. > >> (let ((map (make-sparse-keymap))) >> (define-key map " " map) >> (copy-keymap map)) > > I'm not surprised. There are many ways to address it: > - try and make sure we better handle the "using up all memory" case > rather than crashing. This is very difficult. We already try to do > it, but clearly it's not working that well. > - try and detect such cycles and either signal an error or reproduce the > same cycle in the copy. We have added such things in several other > cases, so we should probably do that. While this is a pretty obscure, Emacs shouldn't crash on stuff like this. I first considered whether just to check for EQ in Fcopy_keymap, but it's possible to have nested keymaps that are mutually recursive, so that won't work. So I just added a recursion counter and refuse to copy when we've reached level 100. It does not protect against the case where the keymap is a char table where one of the entries is the same keymap, but I don't know whether that's a thing. -- (domestic pets only, the antidote for overdose, milk.) bloggy blog: http://lars.ingebrigtsen.no