From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750880AbWFAMTq (ORCPT ); Thu, 1 Jun 2006 08:19:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750902AbWFAMTq (ORCPT ); Thu, 1 Jun 2006 08:19:46 -0400 Received: from public.id2-vpn.continvity.gns.novell.com ([195.33.99.129]:50716 "EHLO emea1-mh.id2.novell.com") by vger.kernel.org with ESMTP id S1750900AbWFAMTp (ORCPT ); Thu, 1 Jun 2006 08:19:45 -0400 Message-Id: <447EF7A8.76E4.0078.0@novell.com> X-Mailer: Novell GroupWise Internet Agent 7.0.1 Beta Date: Thu, 01 Jun 2006 14:20:24 +0200 From: "Jan Beulich" To: "Ingo Molnar" Cc: "Jeff Garzik" , "Tejun Heo" , "Andrew Morton" , "Reuben Farrelly" , Subject: Re: 2.6.17-rc5-mm2 References: <20060601014806.e86b3cc0.akpm@osdl.org> <447EB4AD.4060101@reub.net> <20060601025632.6683041e.akpm@osdl.org> <447EBD46.7010607@reub.net> <20060601103315.GA1865@elte.hu> <20060601105300.GA2985@elte.hu> In-Reply-To: <20060601105300.GA2985@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >Jan, the dwarf2 unwinder apparently fails if we call a NULL function. That is expected behavior, as a NULL program counter (to the unwinder) means end-of-stack-frames. It can't do anything in that case, so the only solution I see is to either - not at all call the unwinder from trap.c if the instruction pointer before the first unwind is not within kernel space, or - force fall-through to the old logic if the first unwind attempt didn't yield a change to either rIP or rSP (implying that in that case there was no unwind information found to start with). What do you think? Jan