From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#41321: 27.0.91; Emacs aborts due to invalid pseudovector objects Date: Fri, 22 May 2020 15:48:40 +0300 Message-ID: <83lflk2l07.fsf@gnu.org> References: <83zha8cgpi.fsf@gnu.org> <83r1vibmyj.fsf@gnu.org> <83imgublku.fsf@gnu.org> <831rncjuwf.fsf@gnu.org> <83tv082mm1.fsf@gnu.org> Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="63471"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 41321@debbugs.gnu.org, monnier@iro.umontreal.ca To: Pip Cet Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Fri May 22 14:49:16 2020 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 1jc76y-000GQ0-4t for geb-bug-gnu-emacs@m.gmane-mx.org; Fri, 22 May 2020 14:49:16 +0200 Original-Received: from localhost ([::1]:38896 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jc76x-0000Rc-09 for geb-bug-gnu-emacs@m.gmane-mx.org; Fri, 22 May 2020 08:49:15 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:44810) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jc76j-0000Om-S4 for bug-gnu-emacs@gnu.org; Fri, 22 May 2020 08:49:01 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:46839) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jc76j-0007Ox-It for bug-gnu-emacs@gnu.org; Fri, 22 May 2020 08:49:01 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jc76j-0007Ao-GE for bug-gnu-emacs@gnu.org; Fri, 22 May 2020 08:49:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 22 May 2020 12:49:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 41321 X-GNU-PR-Package: emacs Original-Received: via spool by 41321-submit@debbugs.gnu.org id=B41321.159015172927557 (code B ref 41321); Fri, 22 May 2020 12:49:01 +0000 Original-Received: (at 41321) by debbugs.gnu.org; 22 May 2020 12:48:49 +0000 Original-Received: from localhost ([127.0.0.1]:58385 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jc76T-0007AL-Nf for submit@debbugs.gnu.org; Fri, 22 May 2020 08:48:49 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:37344) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jc76R-0007A6-Kp for 41321@debbugs.gnu.org; Fri, 22 May 2020 08:48:44 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:47611) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jc76M-0007Lx-6D; Fri, 22 May 2020 08:48:38 -0400 Original-Received: from [176.228.60.248] (port=3051 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1jc76L-0003bP-Gh; Fri, 22 May 2020 08:48:38 -0400 In-Reply-To: (message from Pip Cet on Fri, 22 May 2020 12:39:27 +0000) 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" Xref: news.gmane.io gmane.emacs.bugs:180762 Archived-At: > From: Pip Cet > Date: Fri, 22 May 2020 12:39:27 +0000 > Cc: Stefan Monnier , 41321@debbugs.gnu.org > > > Sorry, I don't follow. "xtype" shows the type of the last result, > > AFAIK, in this case the type of $29. If this changed somehow, either > > we have a bug in .gdbinit or I have been using GDB incorrectly for I > > don't know how many years. > > I think it's most likely to be a GDB bug, and I can't reproduce it here. > > But it's definitely trying to access memory at address 0x18ac04f8, > which corresponds to start_marker. My interpretation of that equality was that both start_marker and the buffer's overlay chain git invalidated because some code relocated objects and unmapped the previously referenced memory, perhaps due to GC. I don't yet have an explanation for how this could happen, so maybe this hypothesis is wrong. > (gdb) p rvoe_arg.location > $35 = (Lisp_Object *) 0x15c9298 > (gdb) xtype > Lisp_Vectorlike > Cannot access memory at address 0x18ac04f8 > (gdb) p rvoe_arg.errorp > $36 = false > > Surely rvoe_arg.location isn't a vectorlike, so that also points to > GDB not dealing with things correctly. rvoe_arg.location should be a pointer to the value of before-change-functions, so yes, it isn't supposed to be vectorlike. But I very much doubt there's such a blatant bug in GDB: this is the latest GDB 9.1, and I'm using these commands from .gdbinit all the time. I tend to think this is somehow part of the bug that caused the crash.