From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753716AbYKRVYa (ORCPT ); Tue, 18 Nov 2008 16:24:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752705AbYKRVYT (ORCPT ); Tue, 18 Nov 2008 16:24:19 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:39571 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752656AbYKRVYS (ORCPT ); Tue, 18 Nov 2008 16:24:18 -0500 Date: Tue, 18 Nov 2008 22:24:05 +0100 From: Ingo Molnar To: Michal Hocko Cc: "Rafael J. Wysocki" , LKML Subject: Re: BUG: using smp_processor_id() in preemptible [00000000] code: latencytop/5621 Message-ID: <20081118212404.GD19150@elte.hu> References: <20081114085820.GA5206@dhcp35.suse.cz> <200811160028.13724.rjw@sisk.pl> <20081118123748.GB5336@dhcp35.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081118123748.GB5336@dhcp35.suse.cz> 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,DNS_FROM_SECURITYSAGE autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] 0.0 DNS_FROM_SECURITYSAGE RBL: Envelope sender in blackholes.securitysage.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Michal Hocko wrote: > On Sun 16-11-08 00:28:12, Rafael J. Wysocki wrote: > > On Friday, 14 of November 2008, Michal Hocko wrote: > > > Hi Ingo, > > > I am experiencing %subj whenever I run latencytop with the rc4 kernel. I > > > have bisected down to the patch 7cbaef9c83e58bbd4bdd534b09052b6c5ec457d5 > > > I am not sure whether this is the same problem as the one reported by > > > Maciej Rutecki (http://lkml.org/lkml/2008/11/12/266), but I have tried > > > your patch (http://lkml.org/lkml/2008/11/12/295) and the problem is > > > still there: > > > BUG: using smp_processor_id() in preemptible [00000000] code: > > > latencytop/5621 > > > caller is native_sched_clock+0x47/0x65 > > > Pid: 5621, comm: latencytop Not tainted 2.6.28-rc4 #13 > > > Call Trace: > > > [] ? printk+0xf/0x11 > > > [] debug_smp_processor_id+0xa2/0xb8 > > > [] native_sched_clock+0x47/0x65 > > > [] proc_sched_show_task+0xd72/0xdd0 > > > [] sched_show+0x39/0x55 > > > [] seq_read+0xee/0x29a > > > [] ? seq_read+0x0/0x29a > > > [] vfs_read+0x87/0x12b > > > [] sys_read+0x3b/0x60 > > > [] sysenter_do_call+0x12/0x25 > > > [] ? cpu_callback+0x238/0x25b > > > > > > I receive flood if this messages immediately after latencytop starts. > > > Reverting 7cbaef9c83e58bbd4bdd534b09052b6c5ec457d5 solves the problem. > > > Config is attached. > > > > > > Let me know if you need some more testing (however I will afk until > > > Tuesday). > > > > Please retest with 2.6.28-rc5. > > Still problem with rc5 (4e14e833ac3b97a4aa8803eea49f899adc5bb5f4). > Ingo's patch from http://lkml.org/lkml/2008/11/16/26 fixes this problem that's upstream now as of v2.6.28-rc5-117-g7f0f598 and later kernels, via this commit: 29d7b90: sched: fix kernel warning on /proc/sched_debug access Ingo