From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Kalman Reti" Newsgroups: gmane.emacs.bugs,gmane.emacs.devel Subject: Re: mark_object crash in 22.1 and latest CVS (as of tonight) Date: Mon, 12 Nov 2007 06:40:23 -0500 Message-ID: <16af2f430711120340q27926877tf976ef397d12df16@mail.gmail.com> References: <16af2f430711081955j3d5e6745gc0f7a50e02d9a892@mail.gmail.com> <16af2f430711090332x39c8c768gb01d1dc6a0e4f427@mail.gmail.com> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1194867641 32428 80.91.229.12 (12 Nov 2007 11:40:41 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 12 Nov 2007 11:40:41 +0000 (UTC) Cc: kalman.reti@gmail.com To: rms@gnu.org, emacs-devel@gnu.org, bug-gnu-emacs@gnu.org Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Mon Nov 12 12:40:46 2007 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1IrXem-0006br-Nv for geb-bug-gnu-emacs@m.gmane.org; Mon, 12 Nov 2007 12:40:45 +0100 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1IrXea-0006jj-PN for geb-bug-gnu-emacs@m.gmane.org; Mon, 12 Nov 2007 06:40:32 -0500 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1IrXeW-0006ik-1R for bug-gnu-emacs@gnu.org; Mon, 12 Nov 2007 06:40:28 -0500 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1IrXeU-0006h0-Ep for bug-gnu-emacs@gnu.org; Mon, 12 Nov 2007 06:40:27 -0500 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1IrXeU-0006gw-Bo for bug-gnu-emacs@gnu.org; Mon, 12 Nov 2007 06:40:26 -0500 Original-Received: from el-out-1112.google.com ([209.85.162.179]) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1IrXeT-0003UD-NA for bug-gnu-emacs@gnu.org; Mon, 12 Nov 2007 06:40:25 -0500 Original-Received: by el-out-1112.google.com with SMTP id s27so271712ele for ; Mon, 12 Nov 2007 03:40:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=5iw9wSuLTRJWFzgjLNlhK6jkJn3MTHEHo4LOBksP7xI=; b=adx2l0SkQC0O5eLi17mFec7Te4eJvumVJq9VfOSgR5RyjW584NwB15WRINprhDmW+0vLQCUUDT85OSGE4sbWd9yFYZk1z0QwzJWrxL7eSywdcrkfwFHnBJ93Wp1lkHwr9urlx44gcukqS/bg9O4wOkp/4bKYQT1HXz7s+VB8OwI= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=EQumI11tYig1oWYIPo5JM1fwAMOPFjz+z8glN/6lIOIp7cguaNrKMJbxD3uL2jxeuwXUXhZQ0Ku2AYAFV07xGfSb9E4rH9ZfuR2CY6hpw5ZaCGH43w9+4YWtcjNIbwMCdc147yIYF32uexD+ZpICSqaZxGeuilfDdtj8QoJguEM= Original-Received: by 10.142.47.6 with SMTP id u6mr154877wfu.1194867623860; Mon, 12 Nov 2007 03:40:23 -0800 (PST) Original-Received: by 10.143.167.19 with HTTP; Mon, 12 Nov 2007 03:40:23 -0800 (PST) In-Reply-To: Content-Disposition: inline X-detected-kernel: by monty-python.gnu.org: Linux 2.4-2.6 (Google crawlbot) X-BeenThere: bug-gnu-emacs@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:16954 gmane.emacs.devel:83043 Archived-At: On Nov 11, 2007 12:22 AM, Richard Stallman wrote: > The first questions are, what object contains the bad pointer? > What data type is it? What data structure is it part of? The gdb pr output near the end of the attachment in my first message shows it is part of a list, which, in turn, is part of a buffer. I assumed someone would recognize WHAT part of a buffer from the contents of the, list, a mixture of conses with marker-in-no-buffer in the car of some and Lisp_Misc_Free in the car of others, the cdr's being negative numbers of pretty small absolute magnitude. If it isn't recognizable from its contents, I'll have to wait till I'm next at work to find out exactly which slot in the buffer this list comes from using gdb. The code I'm running is pretty simple, it executes a shell command (i.e. a perforce command) and then uses search-forward-regexp to find relevant lines in the output, capturing things like revision number or branch using match-string after the regexp matches. The searching is done within a save-excursion which switches to the *Shell Command Output* buffer. I suspect one could reproduce the bug without issuing perforce commands, I'll give that a stab tonight. > > Once you answer those, you can try to figure out how it happened > that the data structure ended up with a bad pointer. > Maybe GC failed to mark that pointer, so the misc object got freed > even though it was still in use. Are there any tools to help with this, e.g. an allocation trace or GC trace? I'm afraid this is the first time I've looked at the Emacs src code. [rest of message elided]