From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Pip Cet Newsgroups: gmane.emacs.bugs Subject: bug#41321: 27.0.91; Emacs aborts due to invalid pseudovector objects Date: Fri, 29 May 2020 11:47:46 +0000 Message-ID: References: <83zha8cgpi.fsf@gnu.org> <83r1vibmyj.fsf@gnu.org> <83imgublku.fsf@gnu.org> <831rncjuwf.fsf@gnu.org> <831rn3nj0u.fsf@gnu.org> <83y2pbm2n9.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="118900"; mail-complaints-to="usenet@ciao.gmane.io" Cc: eggert@cs.ucla.edu, 41321@debbugs.gnu.org, Stefan Monnier To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Fri May 29 13:51:48 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 1jedYB-000Uny-BL for geb-bug-gnu-emacs@m.gmane-mx.org; 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Fri, 29 May 2020 11:49:02 +0000 Original-Received: (at 41321) by debbugs.gnu.org; 29 May 2020 11:48:45 +0000 Original-Received: from localhost ([127.0.0.1]:54007 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jedV2-0000Ud-5S for submit@debbugs.gnu.org; Fri, 29 May 2020 07:48:45 -0400 Original-Received: from mail-oi1-f177.google.com ([209.85.167.177]:39883) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jedV0-0000UP-Mw for 41321@debbugs.gnu.org; Fri, 29 May 2020 07:48:31 -0400 Original-Received: by mail-oi1-f177.google.com with SMTP id a7so1923777oic.6 for <41321@debbugs.gnu.org>; Fri, 29 May 2020 04:48:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ulwyNIjxxy/Hoj0CaIboLC8jP4zBI5AfIFBlMl20QUM=; b=jgcz2ompBIf/t+n4PWM2TB1gymbuAQ9fB6x73FuoCZUIVg7uzsfym/4A/bbQ86/C9t mIH7clfe95PsgQLxPEkcOttOgIPw4ttvnJtGJ4m/ZWP+UKG8Ml6rq01pTOEHCeVYLi83 llX2uuOMo8PO1OQ/YFIVxFkYmptH+177kw17FVpM1HHY88iXrzj2sedB9qzWDRplrV7/ sCa9/zJ9Z9p6gJMUiIM1FVCA81PGxDnXH8axgLJ2lRhB1NbG3rc8yCJ3JuD4ucowH7mf DMEObL191L/VYTqIjVcoh6D4tVzHDxwkCnAw0rdn7wvt2MLRiFdeADSOdbELXzxBkGRE wGtg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ulwyNIjxxy/Hoj0CaIboLC8jP4zBI5AfIFBlMl20QUM=; b=FJp/vqMjHz/nYnvwHX/uvcxo/kUokUdOOAJjNBRLI2RM49ZGpA9zGsE3gBHmq/xCdn dVYvPt14OUwCnQ+mqTm5WoR8DDPeyxYtGqsfw/rPvLsNPsikS+03PbIl1Ai1/JCWm1Vv mKHfQFbs6FFeEKJjUiRjdklZcF8sjIZw5fuXtiond7uWp36qDRIZkgcQLlzMKli0uVGK oKYkh8DjJEdVCQshtXpqH2lPqWTVsgnJ1LmH3cWYTItzcavQFMlwQr//fSCglkrwIVmT iRE2mQ6iIb6o58DT45zgjG2qtneU7r1g2ZG9McOKaLDSPy7ZlVszTUhjuDIqRQrhPR0L i3pQ== X-Gm-Message-State: AOAM5334MbyP1AbeLkWuqwavn806dHb4WrBUpdBYhTQ/U1MZXvV/RfWR o+CV4P44H3Vl9c8jEpuH+4WSmpyZw3I1oZcgwFE= X-Google-Smtp-Source: ABdhPJysMR5ng0UmA7XFeJbjI2XF8r+9eshaehMBdy2HA4jUuMNKJohD4Px/GI2ZYEJxwyxmYN2bzxtUQj/ix8q0Fgk= X-Received: by 2002:aca:b708:: with SMTP id h8mr5148633oif.122.1590752903684; Fri, 29 May 2020 04:48:23 -0700 (PDT) In-Reply-To: <83y2pbm2n9.fsf@gnu.org> 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:181180 Archived-At: On Fri, May 29, 2020 at 10:55 AM Eli Zaretskii wrote: > > From: Pip Cet > > Date: Fri, 29 May 2020 10:34:20 +0000 > > Cc: Paul Eggert , Stefan Monnier , 41321@debbugs.gnu.org > > > > > . There's nothing wrong with GDB's xtype command: it fails when a Lisp > > > object encodes a pointer to invalid memory: > > > > (gdb) p last_marked[497] > > $100 = XIL(0x439c370) > > (gdb) xtype > > Lisp_Vectorlike > > Cannot access memory at address 0x1ffac2a8 > > > > Again, that can't be right. $100 is a Lisp_Symbol, not a vectorlike, > > and it's not at address 0x1ffac2a8. > > > > So my suspicion remains that this is a gdb bug, and it appears to be a > > reproducible one! > > There's no bug: I believe there is. > the $size variable was not updated inside pvectype > because the 'set' command tried to access invalid memory. Why would pvectype be called at all? xtype should have said "Lisp_Symbol", not "Lisp_Vectorlike", and never gotten to pvectype at all. Feel free to try that, in a fresh GDB session: p 0x439c370 xtype > So the rest > is using the stale value of $size. Puff! no miracle and no bug. Which rest? There's no message after "Cannot access memory at address 0x1ffac2a8" > You just don't need to assign too much importance to the address the > error message displays, it might not be the problematic address. Or there might not be a problematic address, because xtype is somehow using the value of $ which it used when it encountered the initial bug even for subsequent calls. It doesn't do that here.