From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161466AbWHDVKW (ORCPT ); Fri, 4 Aug 2006 17:10:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161471AbWHDVKW (ORCPT ); Fri, 4 Aug 2006 17:10:22 -0400 Received: from adsl-69-232-92-238.dsl.sndg02.pacbell.net ([69.232.92.238]:45983 "EHLO gnuppy.monkey.org") by vger.kernel.org with ESMTP id S1161466AbWHDVKU (ORCPT ); Fri, 4 Aug 2006 17:10:20 -0400 Date: Fri, 4 Aug 2006 14:10:11 -0700 To: Darren Hart Cc: LKML , Thomas Gleixner , Ingo Molnar , "Bill Huey (hui)" , Steven Rostedt Subject: Re: [BUG -rt] Double OOPs - thread_info free race / printk recursive lock Message-ID: <20060804211011.GA20342@gnuppy.monkey.org> References: <200608041043.06446.dvhltc@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200608041043.06446.dvhltc@us.ibm.com> User-Agent: Mutt/1.5.11+cvs20060403 From: Bill Huey (hui) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 04, 2006 at 10:43:05AM -0700, Darren Hart wrote: > We've seen very rarely over the last few months, on various -rt kernels. The > latest reproduction is on 2.6.16-rt22 (+some minor fixups). Analysis of the > vmcore produced by kdump suggests two problems: > 1) An invalid pointer dereference in cache_flusharray() which causes the page > fault. My guess is that this is after some bogus stuff going on after the real event. > 2) Then printk calls kmalloc when trying to print the oops, which grabs a > recursive lock and prints a different oops. Can't say for sure, but this sounds a lot like the problem I've been dealing with in free_task(). The stack trace is pretty contorted and it's been difficult to unwind it in any meaningful manner, although I'm making progress. Writing some tools to deal with this now. bill