From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755016AbYIIHcW (ORCPT ); Tue, 9 Sep 2008 03:32:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753540AbYIIHcO (ORCPT ); Tue, 9 Sep 2008 03:32:14 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:53757 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753177AbYIIHcN (ORCPT ); Tue, 9 Sep 2008 03:32:13 -0400 Date: Tue, 9 Sep 2008 09:31:53 +0200 From: Ingo Molnar To: Jan Beulich Cc: Yinghai Lu , tglx@linutronix.de, linux-kernel@vger.kernel.org, hpa@zytor.com Subject: Re: [PATCH] x86: x86_{phys,virt}_bits field also for i386 (v2) Message-ID: <20080909073153.GA10049@elte.hu> References: <48C13D1C.76E4.0078.0@novell.com> <20080905150030.GD10292@elte.hu> <48C51F8D.76E4.0078.0@novell.com> <20080908134019.GB11993@elte.hu> <20080908185417.GA17654@elte.hu> <48C6406E.76E4.0078.0@novell.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48C6406E.76E4.0078.0@novell.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jan Beulich wrote: > >>> Ingo Molnar 08.09.08 20:54 >>> > > > >-tip testing found various kernel crashes on 32-bit testboxes and i've > >bisected it down to: > > > >... > > > >a typical crash is like the one attached below. It's due to the ioremap > >failing. The drivers/char/rio/rio_linux.c driver probes these addresses: > > > > static int rio_probe_addrs[] = { 0xc0000, 0xd0000, 0xe0000 }; > > > >which is questionable ... > > No, they look absolutely valid, they're ISA ROM addresses. yeah - questionable in the sense of assuming that it's all non-RAM. But there's no better way to probe for ROMs i guess. > > for now i've reverted it from current tip/master, see commit > > e3fdd129901. (you can reinstate the commit by doing "git revert > > e3fdd1299" > > > > Even if we decided to fail these ioremaps it would be better to emit > > a warning instead of crashing the box. > > We shouldn't fail them, they're valid. What the crash means is that > even addresses below 1Mb are considered out of range, which I can only > take as x86_phys_bits being zero (or a bogus very small number) on > secondary (or all) CPUs. However, looking at the call tree I can't see > how that could happen (provided CPUID doesn't produce garbage output): > > - smp_store_cpu_info(), as it always did, pre-initializes the new CPU's > info with boot_cpu_data, and calls identify_secondary_cpu() > - identify_secondary_cpu() calls identify_cpu() > - identify_cpu() pre-sets x86_phys_bits to 32, and since the field didn't > exist for 32-bits before, nothing should be able to clear or otherwise > alter it there's nothing weird about this testbox (it's a usual whitebox) - and two other testboxes failed as well after some time (no crashlog available from them). A 64-bit testbox didnt fail so it seems 32-bit only. Ingo