From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#63711: 30.0.50; Crash in xdisp.c when it->string is 0x0 Date: Thu, 25 May 2023 18:11:39 +0300 Message-ID: <834jo0mono.fsf@gnu.org> References: <83ilcgn9ud.fsf@gnu.org> <835y8gmt3f.fsf@gnu.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="39420"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 63711@debbugs.gnu.org To: Thomas Fitzsimmons Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Thu May 25 17:12:25 2023 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 1q2Cdc-0009zu-Nu for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 25 May 2023 17:12:24 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1q2CdI-0002Kv-NP; Thu, 25 May 2023 11:12:04 -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 1q2CdG-0002KJ-Ba for bug-gnu-emacs@gnu.org; Thu, 25 May 2023 11:12:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1q2CdG-0004ZL-3i for bug-gnu-emacs@gnu.org; Thu, 25 May 2023 11:12:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1q2CdF-0006FH-TI for bug-gnu-emacs@gnu.org; Thu, 25 May 2023 11:12:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Thu, 25 May 2023 15:12:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 63711 X-GNU-PR-Package: emacs Original-Received: via spool by 63711-submit@debbugs.gnu.org id=B63711.168502747923937 (code B ref 63711); Thu, 25 May 2023 15:12:01 +0000 Original-Received: (at 63711) by debbugs.gnu.org; 25 May 2023 15:11:19 +0000 Original-Received: from localhost ([127.0.0.1]:47832 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1q2CcZ-0006E1-Ds for submit@debbugs.gnu.org; Thu, 25 May 2023 11:11:19 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:58838) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1q2CcX-0006Dn-0b for 63711@debbugs.gnu.org; Thu, 25 May 2023 11:11:18 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q2CcQ-0004Ch-UA; Thu, 25 May 2023 11:11:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=WmZUnAYuSf2V3OoHzpmkHwxdduGGfz5Qtao3S8oQhI0=; b=mAZX1PBYktjb d7SpFUMJtkafY//GCAjUVK2EjBbTNJlgmvk/oROsbANgivx67tzIzDoYhzDPVYUeXs1zAxiDdn0yn F5AXnN9245ke3vAWHrLNKx24zBQV8K7edKo4vMhqjsAzK/Fx7vDygSqr/B+cBkYQ+W5MSeE/ayYpH jecnySvqGjn5ri6A44aT8FG5T/TxGiVkKPOwyQ7HbfKGVOObC++WlEBSYXLWVj5gxNPFU93JI6Wik yj9ZWAPQUZe9v/CUjuAtlwPkn1YxJWRgmywzjWKiYKqwMXIR2vG5mRLGMKuT/sU9crqVOfKCopqGv 1Y8a28ytgly86TeJpkFlRA==; Original-Received: from [87.69.77.57] (helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q2CcQ-0006Wb-4q; Thu, 25 May 2023 11:11:10 -0400 In-Reply-To: (message from Thomas Fitzsimmons on Thu, 25 May 2023 09:50:44 -0400) 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-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.bugs:262374 Archived-At: > From: Thomas Fitzsimmons > Cc: 63711@debbugs.gnu.org > Date: Thu, 25 May 2023 09:50:44 -0400 > > > (gdb) p (*BYTE_POS_ADDR(pos->pos.bytepos))@100 > > > > (Here 100 is the number of bytes to display; feel free to use more if > > 100 is insufficient.) > > $14 = "\000\000;; js.el --- Major mode for editing JavaScript -*- lexical-binding: t -*-\n\n;; Copyright (C) 2008-" > > > Once you do understand what buffer is this, please try to describe the > > overlays at buffer position pos->pos.charpos in that buffer, if there > > are supposed to be any overlays there. > > (gdb) p pos->pos.charpos > $16 = 0 > > So I guess the first 100 characters printed above already shows the > context at pos->pos.charpos? Are those leading zero-bytes expected? No. And pos->pos.charpos isn't supposed to be zero, since buffer positions start from 1. So something is very wrong there. Please show the results of the following commands: (gdb) p PT (gdb) frame 1 (gdb) prow (gdb) pgrow (gdb) frame 2 (gdb) pgrowx start_row (gdb) p first_reusable_row - start_row (gdb) p first_row_to_display - start_row (gdb) p first_row_to_display->y (gdb) p window_text_bottom_y(w) > > That position is supposed to be the first position of a screen line, > > i.e. the position of the leftmost character on display in that line. > > I was experimenting with font-locking JavaScript. Maybe I put Emacs > into a strange state that way (though it still shouldn't be crashable). > I can't visually inspect the affected window anymore; it was an X11 > window, tunneled through an SSH connection which I've since closed. But there weren't supposed to be any overlays at the beginning of the buffer, right? Can you describe your experiments with font-locking JavaScript? Which display-related features did you try?