From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754169AbYIENxB (ORCPT ); Fri, 5 Sep 2008 09:53:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753218AbYIENwx (ORCPT ); Fri, 5 Sep 2008 09:52:53 -0400 Received: from ns1.q-leap.de ([153.94.51.193]:56623 "EHLO mail.q-leap.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752909AbYIENww (ORCPT ); Fri, 5 Sep 2008 09:52:52 -0400 From: Bernd Schubert To: Arjan van de Ven Subject: Re: frame unwinder patches Date: Fri, 5 Sep 2008 15:52:47 +0200 User-Agent: KMail/1.9.9 Cc: linux-kernel@vger.kernel.org, Andi Kleen References: <200809051119.21699.bs@q-leap.de> <20080905063317.5e3a2b2c@infradead.org> In-Reply-To: <20080905063317.5e3a2b2c@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200809051552.47929.bs@q-leap.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 05 September 2008 15:33:17 Arjan van de Ven wrote: > On Fri, 5 Sep 2008 11:19:21 +0200 > > Bernd Schubert wrote: > > > not printing the ? would be trivial (for some backtraces we do > > > that), but so far hasn't been seen as desirable because you lose > > > information in those hard-to-debug cases when you need anything you > > > can get from the backtrace. > > > > I see your point, but in most cases it is rather annoying. > > ... if you see backtraces regularly there's something wrong ;-) It always depends on what you are doing. Presently I'm fixing the reset-handler of the mpt fusion driver and since I'm not $hardcore_kernel_hacker_with_super_scsi_knowlegde, but only know C and a little bit about the kernel API I insert dump_stack() and printks all over the place into the code to understand what is going on. Well, this reset part is mostly done, now this problem: http://marc.info/?l=linux-scsi&m=118039573814323&w=2 So yes, there is something wrong ;) Unfortunately so far nobody cared about these bugs we are hitting regularily. > > (and if you really care it's 1 line of code to turn it off) It is not only this, I think the dwarf2 stack unwinder patches provide by far better traces than the in-kernel unwinder. At least ever since I applied these patches to our kernels, I was able to read the stack dumps... Cheers, Bernd -- Bernd Schubert Q-Leap Networks GmbH