From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757741AbYERP5n (ORCPT ); Sun, 18 May 2008 11:57:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754189AbYERP5d (ORCPT ); Sun, 18 May 2008 11:57:33 -0400 Received: from mailout01.t-online.de ([194.25.134.80]:49066 "EHLO mailout01.t-online.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752411AbYERP5c convert rfc822-to-8bit (ORCPT ); Sun, 18 May 2008 11:57:32 -0400 From: =?iso-8859-1?q?J=FCrgen_Mell?= Reply-To: j.mell@t-online.de To: Steven Rostedt Subject: Re: CONFIG_PREEMPT causes corruption of application's FPU stack Date: Sun, 18 May 2008 17:57:10 +0200 User-Agent: KMail/1.9.6 (enterprise 20071221.751182) References: <200805171831.08490.j.mell@t-online.de> <20080518150733.GC8100@goodmis.org> In-Reply-To: <20080518150733.GC8100@goodmis.org> Cc: linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200805181757.10747.j.mell@t-online.de> X-ID: VmzuZgZf8hq--C1zTlrQRUGTTj3c00LZsc6h2YPxoZ+HKSSOxb8Ub+KZ6m-pGUrg3M X-TOI-MSGID: 867f2d2d-87e3-4199-b41b-cf40059ede41 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sonday, 18. May 2008, you wrote: > On Sat, May 17, 2008 at 06:31:08PM +0200, J?rgen Mell wrote: > > I tracked this down to a single kernel configuration option. If > > CONFIG_PREEMPT is set to 'y' the application will start crashing. If > > CONFIG_PREEMPT is replaced by CONFIG_PREEMPT_VOLUNTARY, the > > application will run without errors. > > > > The problem is reproducible in so far as the error always occurs when > > CONFIG_PREEMPT is set, but the time to the first occurrence varies > > greatly from some minutes up to more than 10 CPU hours. > > > > I found this error first on an openSUSE kernel 2.6.22.17-0.1-rt. I > > verified the problem on the following kernel versions: > > > > openSUSE 2.6.22.17-0.1-default > > openSUSE 2.6.23.17-ccj64-rt > > kernel.org 2.6.26-rc1 > > kernel.org 2.6.26-rc2-git5 > > So you see this error in both the SuSE RT kernel, *and* mainline > kernel.org? Yes, that is correct. The error is present from the 2.6.22 SUSE kernel up to the most recent mainline kernel. It is also present in the standard SUSE kernel, if I just modify *only* CONFIG_PREEMPT. What makes me wonder: I am using the machine in a production environment for programming, multi-media etc. Why does only the Einstein program catch the SIGFPE? Normally I would expect other programs to crash, too, if the problem is present. But up to now this never happened. > If you see it in the kernel.org kernel, can you please do a git-bisect > to see which commit caused the problem? This is a bit of a problem. I do not know whether there was *ever* a kernel version with CONFIG_PREEMPT and without this problem as I have not tried any older kernel version yet. I will go back to SUSE 10.2 and try the 2.6.18 kernel that comes with it. Bye, Jürgen