From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: gdb doesn't print Lisp backtrace in some circumstances. Date: Sat, 13 Apr 2024 10:07:09 +0000 Message-ID: References: <86pluusunr.fsf@gnu.org> <86mspyss94.fsf@gnu.org> <86jzl2sogq.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="33864"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Apr 13 12:08:04 2024 Return-path: Envelope-to: ged-emacs-devel@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 1rvaIm-0008aD-A7 for ged-emacs-devel@m.gmane-mx.org; Sat, 13 Apr 2024 12:08:04 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rvaI4-00086w-Do; Sat, 13 Apr 2024 06:07:20 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rvaI0-00086U-H7 for emacs-devel@gnu.org; Sat, 13 Apr 2024 06:07:16 -0400 Original-Received: from mail.muc.de ([193.149.48.3]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rvaHy-0007CK-1h for emacs-devel@gnu.org; Sat, 13 Apr 2024 06:07:16 -0400 Original-Received: (qmail 77264 invoked by uid 3782); 13 Apr 2024 12:07:10 +0200 Original-Received: from muc.de (p4fe15e20.dip0.t-ipconnect.de [79.225.94.32]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Sat, 13 Apr 2024 12:07:09 +0200 Original-Received: (qmail 10602 invoked by uid 1000); 13 Apr 2024 10:07:09 -0000 Content-Disposition: inline In-Reply-To: <86jzl2sogq.fsf@gnu.org> X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de Received-SPF: pass client-ip=193.149.48.3; envelope-from=acm@muc.de; helo=mail.muc.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:317706 Archived-At: Hello, Eli. On Fri, Apr 12, 2024 at 16:24:53 +0300, Eli Zaretskii wrote: > > Date: Fri, 12 Apr 2024 13:18:15 +0000 > > Cc: emacs-devel@gnu.org > > From: Alan Mackenzie > > > One way of avoiding all this tedious manual work is to try to catch > > > the problem with a breakpoint in a running Emacs, not in a core dump. > > That won't work for this situation. The seg fault is happening whilst > > loading isearch.el from loadup.el during early building. I don't have a > > running Emacs to probe it with. > I don't see why can't you have a running Emacs. You just need to run > temacs under GDB instead of emacs, and you need to run the exact > command that crashes under GDB. To see what command crashes, run > "make V=1", to force make to display every command it runs in its > entirety. Maybe I'll try that. What I eventually did yesterday was to code in a limit of 150 to the length of the last argument in Fapply, signalling an error when it was higher. Even this (Lisp) backtrace is difficult to decypher. The backtrace I got is a mess. The problem has a lot to do with generic functions, and cl-generic.el is as good as entirely undocumented. Didn't we have somebody volunteering to fix this some months ago? Has anything come of that, yet? -- Alan Mackenzie (Nuremberg, Germany).