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: Sun, 24 May 2020 18:03:57 +0000 Message-ID: References: <83zha8cgpi.fsf@gnu.org> <83r1vibmyj.fsf@gnu.org> <83imgublku.fsf@gnu.org> <831rncjuwf.fsf@gnu.org> <83h7w5xvfa.fsf@gnu.org> <83y2phwb9x.fsf@gnu.org> <83r1v9w9vi.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="111907"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 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 Sun May 24 20:05:16 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 1jcuzs-000SzW-Aj for geb-bug-gnu-emacs@m.gmane-mx.org; 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Sun, 24 May 2020 18:05:02 +0000 Original-Received: (at 41321) by debbugs.gnu.org; 24 May 2020 18:04:41 +0000 Original-Received: from localhost ([127.0.0.1]:38650 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jcuzI-0006f9-Qw for submit@debbugs.gnu.org; Sun, 24 May 2020 14:04:41 -0400 Original-Received: from mail-ot1-f51.google.com ([209.85.210.51]:38603) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jcuzI-0006ew-3J for 41321@debbugs.gnu.org; Sun, 24 May 2020 14:04:40 -0400 Original-Received: by mail-ot1-f51.google.com with SMTP id o13so12300935otl.5 for <41321@debbugs.gnu.org>; Sun, 24 May 2020 11:04:40 -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=AadenALC9XcefOWndGXdd48cEQ8Zm9n2scqMnBtIHuk=; b=TI/D2Wc4vPSRXkstjbv/bUPQNw3eWUFuoMi+osmo4suX2g3LQWogrI6DxyeReTS6Oz nAGUIAm7p07LHbNepyVeW5VEGfJ7e5wrp203dWehk1uFePyt1kfBENOqQuEJ3rSyL1mF uPQBF1qM6pQgLOzsVV0H+RjEdyxKmrXXmRXR37G1oU+TH213y3QTmpv3OQ+4asII4vMu nR2F6OikR6/ldh6tCEG4Ly2t5DpBFJoTJ5btUObfXhK2FVCfjrxuLjFnapfTMW7w53DZ oVRC59WSDxnvghDP0aMX5xH3w9KGYoojGCWWw2WudznIk1Ajp8H3wKobHwHKt6jKUp9b CxCg== 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=AadenALC9XcefOWndGXdd48cEQ8Zm9n2scqMnBtIHuk=; b=mjKVTc85ziCqjcdZ2j35k1R1LLIQ/6bH9oVzZOgD2ZyS/+wwB6Z7xLvgbamNRWq25F AJFlfuUMubBL6AuTAZPFRlZOaSAJLuBEjNuirUME+PRlYnACY88ThxGV07YkwBTKfaKY RC4YW91fCsTcLMbB2DtIxyvEnA+Bmpfp1xADRcaMwOPobtee2hlwwMta3i9qZ4SN2xYs 7uJJmgK/uk7p9gKN+EdSBa98ZGTjrjh5IeHqxhm9PQPbRb1jPa3VAxnLBpR5nI1EckvC 83g1C0EGyvN9JVZg2ChUsd77g45/pyC3o3GkPpVzy9kyzbEtJsrBOax8/iTgzZUO20gM ToOA== X-Gm-Message-State: AOAM531db1rOdJLNNN1cRK+yGP4fcid+kSuT+5Gr5dDQStmwcHcLLHYV JBu1KeADJjL2vqprKPQ+qMlD/6sgu53alkTYZQE= X-Google-Smtp-Source: ABdhPJz4ho4WHuXhRDBVvs7UftLYjDKijmcxlGTY1qJiSQuXyJDIEqOV594EyqLTCYgmf0K+6Naxb0ve5TxhT+9Ib1c= X-Received: by 2002:a05:6830:61b:: with SMTP id w27mr16381061oti.154.1590343474468; Sun, 24 May 2020 11:04:34 -0700 (PDT) In-Reply-To: <83r1v9w9vi.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:180916 Archived-At: On Sun, May 24, 2020 at 4:55 PM Eli Zaretskii wrote: > And here's a reminder from how the same looked in the session that> segfaulted: > > (gdb) p current_buffer->overlays_before > $28 = (struct Lisp_Overlay *) 0x170cb080 > (gdb) p $28->start > $29 = XIL(0xa0000000170cb040) > (gdb) xtype > Lisp_Vectorlike > Cannot access memory at address 0x18ac04f8 That should read "Cannot access memory at address 0x170cb080". It doesn't. It doesn't tell you whether the memory at page 0x170cb000 is mapped, because gdb, for whatever reason (a bug in .gdbinit, a bug in gdb, some weird command entered at the gdb prompt before the transcript started, or even, as you yourself suggested, somehow as the result of the memory corruption that caused the crash), looked in the wrong place. Instead, it tells you that the page at 0x18ac0000 isn't mapped. Which we knew. > (gdb) p $28->next > $30 = (struct Lisp_Overlay *) 0x13050320 > (gdb) p $28->next->start > $31 = XIL(0xa000000016172310) > (gdb) xtype > Lisp_Vectorlike > Cannot access memory at address 0x18ac04f8 Same here. It should read "Cannot access memory at address 0x16172310". > If you still claim that I didn't demonstrate that the buffer's overlay > chain got corrupted I do, of course. The message GDB prints simply does not say anything problematic about the buffer's overlay chain. > as part of the bug that caused the segfault, > please point out what I missed here. You omitted the third call to xtype, which was even more clearly nonsensical: xtype was misbehaving. We don't know in which way it was misbehaving. So there's no evidence either way. FWIW, running into gdb bugs is something that happens to me almost on a regular basis. There's no point reporting those, as there's generally no response. In your case, you're in an unusual environment with a rather large and complicated .gdbinit file which does very strange things to avoid running into GDB bugs that we know about. All that increases the likelihood of your encountering a gdb bug that no one else has, or that has been reported but never responded to.