From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Andreas Schwab Newsgroups: gmane.emacs.devel Subject: Re: [Emacs-diffs] master 8ba156f: Attempt to avoid crashes in plist-member Date: Tue, 13 Oct 2015 10:00:26 +0200 Message-ID: References: <20151012170324.17966.77@vcs.savannah.gnu.org> <83k2qro5eg.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1444723276 21280 80.91.229.3 (13 Oct 2015 08:01:16 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 13 Oct 2015 08:01:16 +0000 (UTC) Cc: Stefan Monnier , emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Oct 13 10:01:09 2015 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZluWA-0001qd-JU for ged-emacs-devel@m.gmane.org; Tue, 13 Oct 2015 10:01:06 +0200 Original-Received: from localhost ([::1]:32886 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZluWA-0006TE-10 for ged-emacs-devel@m.gmane.org; Tue, 13 Oct 2015 04:01:06 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:37706) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZluVd-0006SR-4s for emacs-devel@gnu.org; Tue, 13 Oct 2015 04:00:37 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZluVc-0003gb-2x for emacs-devel@gnu.org; Tue, 13 Oct 2015 04:00:32 -0400 Original-Received: from mx2.suse.de ([195.135.220.15]:32779) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZluVX-0003gA-FB; Tue, 13 Oct 2015 04:00:27 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Original-Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 587FFAD73; Tue, 13 Oct 2015 08:00:25 +0000 (UTC) X-Yow: LOU GRANT froze my ASSETS!! In-Reply-To: <83k2qro5eg.fsf@gnu.org> (Eli Zaretskii's message of "Tue, 13 Oct 2015 05:42:47 +0300") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x (no timestamps) [generic] X-Received-From: 195.135.220.15 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:191431 Archived-At: Eli Zaretskii writes: >> From: Stefan Monnier >> Cc: Eli Zaretskii >> Date: Mon, 12 Oct 2015 21:07:00 -0400 >> >> > Attempt to avoid crashes in plist-member >> >> > * src/fns.c (Fplist_member): Don't call QUIT between a CONSP test >> > and a call to XCDR. (Bug#21655) >> >> I have no objection to the patch itself, but I must say that I wonder >> how it can avoid crashes. IOW why would calling QUIT between a CONSP test >> and a call to XCDR be dangerous? > > QUIT could call some Lisp. > > How else would you explain a segfault in that loop? The only chance I see if garbage collection mistakenly collects the referenced cell. But that wouldn't be cured by the change. Andreas. -- Andreas Schwab, SUSE Labs, schwab@suse.de GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7 "And now for something completely different."