From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Daniel Colascione Newsgroups: gmane.emacs.bugs Subject: bug#27585: segfault when evaluating a file containing only backticks Date: Thu, 06 Jul 2017 08:52:44 -0700 Message-ID: <6EDA4B5A-B345-4A8A-8F03-2925B671505B@dancol.org> References: <1499235670.28433.1@ssh.steve.org.uk> <83van6n2ty.fsf@gnu.org> <1499280931.14677.1@ssh.steve.org.uk> <83tw2qmzsl.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1499356394 1566 195.159.176.226 (6 Jul 2017 15:53:14 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 6 Jul 2017 15:53:14 +0000 (UTC) User-Agent: K-9 Mail for Android Cc: 27585@debbugs.gnu.org To: Eli Zaretskii ,Steve Kemp Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Thu Jul 06 17:53:08 2017 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dT95U-0008KJ-S7 for geb-bug-gnu-emacs@m.gmane.org; Thu, 06 Jul 2017 17:53:05 +0200 Original-Received: from localhost ([::1]:52083 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dT95Y-00052q-KF for geb-bug-gnu-emacs@m.gmane.org; Thu, 06 Jul 2017 11:53:08 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:40722) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dT95T-00052k-DY for bug-gnu-emacs@gnu.org; Thu, 06 Jul 2017 11:53:04 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dT95S-0004ly-KR for bug-gnu-emacs@gnu.org; Thu, 06 Jul 2017 11:53:03 -0400 Original-Received: from debbugs.gnu.org ([208.118.235.43]:52662) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dT95S-0004lp-Gg for bug-gnu-emacs@gnu.org; Thu, 06 Jul 2017 11:53:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1dT95S-0007Go-5B for bug-gnu-emacs@gnu.org; Thu, 06 Jul 2017 11:53:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Daniel Colascione Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Thu, 06 Jul 2017 15:53:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 27585 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 27585-submit@debbugs.gnu.org id=B27585.149935637827937 (code B ref 27585); Thu, 06 Jul 2017 15:53:02 +0000 Original-Received: (at 27585) by debbugs.gnu.org; 6 Jul 2017 15:52:58 +0000 Original-Received: from localhost ([127.0.0.1]:55339 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dT95O-0007GV-Df for submit@debbugs.gnu.org; Thu, 06 Jul 2017 11:52:58 -0400 Original-Received: from dancol.org ([96.126.100.184]:34100) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dT95M-0007GN-G8 for 27585@debbugs.gnu.org; Thu, 06 Jul 2017 11:52:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=dancol.org; s=x; h=Message-ID:From:CC:To:Subject:Content-Transfer-Encoding:Content-Type:MIME-Version:References:In-Reply-To:Date; bh=hOcImo3+C+EnnXlWPKrIpmjzh375OhnG1773PUt9Fv4=; b=DVdsTS+5KqsRkaw5yRAZ9ICTHnxRgFfTfl0SyNpckEqgDZ3/YZ1Bnv6b3J8pvDKjGSMyBd9c6LNG4+rvFMr9vBx/REbodJDFtBzaHB41DtTfUNSDp7qK+3ReFXlDBqnNQ3CBdhB3zvbE8pGh7f/HLXlYJ1jOrs1rEMcbm1IGBaI/sa47bk6SAIiI4yhvg+qq2T7F8Zo5zlqCWX93cZrfQ26VRJgj3FXAMlZinhCfSngdTJg5HSdcw09ET1c/fHprecpP9UeTzqHmkA83gWDEsQJpoXyDY4QsAqjHCOu+uqTk11mu0WLOd325VEG6Zx0Syd8ZiKsp0HEGY41LWVSv9Q==; Original-Received: from [2601:602:9803:17b3:e939:8d47:78c0:9e9] by dancol.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1dT95J-00075Q-VM; Thu, 06 Jul 2017 08:52:54 -0700 In-Reply-To: <83tw2qmzsl.fsf@gnu.org> 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: 208.118.235.43 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:134276 Archived-At: On July 5, 2017 12:47:22 PM PDT, Eli Zaretskii wrote: >> From: Steve Kemp >> Date: Wed, 05 Jul 2017 18:55:31 +0000 >>=20 >> > See above: the machinery to try and prevent it exists, but it >doesn't >> > always succeed=2E And it really can't be 100% reliable=2E So I'm >unsure >> > what did you expect, and why=2E >>=20 >> Honestly? I expect Emacs to not crash=2E > >You wrote a program that triggers infinite recursion=2E Such programs >will crash in most, if not all, languages=2E So your expectations are >unrealistic=2E > >> I expect evaluating lisp to not kill the editor > >Valid Lisp, I agree=2E But yours isn't=2E > >Moreover, there are those among us (I'm not one of them) who thinks >Emacs shouldn't even try to recover from stack overflow, they say it >should crash hard right there and then=2E Native stack? Certainly=2E The current approach, a signal handler that lon= gjmps to top-level, cannot possibly work reliability, since it interrupts a= nd abandons whatever the code is doing=2E If it has some kind of lock held = and you try to take that lock again, you deadlock=2E Data structures might = be in completely incoherent states=2E The last time we had this discussion,= someone asserted that the worst that could happen might be a "memory leak"= =2E That's very wrong=2E This signal handler is a huge, ticking time bomb, and I completely turn it= off in my Emacs=2E Everyone else should too=2E Recovering when elisp blows the stack is a different matter=2E > >So your expectations are not necessarily shared, even as aspirations, >by some developers=2E > >> > IOW: why would someone want to run such a silly "program"? >>=20 >> In the real world? Nobody=2E > >Then why are we discussing this use case? Let's talk about >more practical and interesting cases=2E