From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753669AbYIVPNi (ORCPT ); Mon, 22 Sep 2008 11:13:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752682AbYIVPN3 (ORCPT ); Mon, 22 Sep 2008 11:13:29 -0400 Received: from ik-out-1112.google.com ([66.249.90.176]:49803 "EHLO ik-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752607AbYIVPN2 (ORCPT ); Mon, 22 Sep 2008 11:13:28 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:reply-to:user-agent:mime-version:to:cc:subject :references:in-reply-to:x-enigmail-version:content-type :content-transfer-encoding; b=skERzdlhJHKgJK5jPYX+3WAy90BFbngSFQkDIN/C61t6ks6R4Q49f0Q8W5tfbkpFCm cKryvD8rcrUewJPZb7LzEKPL42eiZrCmmiiM3X5CR1SVZ15vwTbWwWXL47zljZZOTAZU 0xqmUAsa1yY7zbHsBRJ8cPtDUI29DKN34FKtk= Message-ID: <48D7B60F.4000704@gmail.com> Date: Mon, 22 Sep 2008 17:13:19 +0200 From: Andrea Righi Reply-To: righi.andrea@gmail.com User-Agent: Thunderbird 2.0.0.16 (X11/20080724) MIME-Version: 1.0 To: Ingo Molnar CC: robert.richter@amd.com, akpm@linux-foundation.org, oprofile-list@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH -mm] oprofile: BUG: using smp_processor_id() in preemptible code References: <1221908320-7183-1-git-send-email-righi.andrea@gmail.com> <20080922102524.GB30137@elte.hu> <20080922102834.GA32692@elte.hu> In-Reply-To: <20080922102834.GA32692@elte.hu> X-Enigmail-Version: 0.95.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > * Ingo Molnar wrote: > >>> + local_irq_save(flags); >>> __get_cpu_var(switch_index) = 0; >>> + local_irq_restore(flags); >> either use __raw_get_cpu_var() if we are for sure not preemptible >> here, or fix the preemption status of this codepath. > > i've applied the patch below instead to tip/oprofile - agreed? > > Ingo Seems to work fine. Thanks, -Andrea > > ------------> > From 45f197ade73ba95681b9803680c75352fc0a1c0a Mon Sep 17 00:00:00 2001 > From: Andrea Righi > Date: Sat, 20 Sep 2008 12:58:40 +0200 > Subject: [PATCH] x86, oprofile: BUG: using smp_processor_id() in preemptible code > > Add __raw access before setting per cpu variable switch_index, to avoid > the following BUG: > > [ 449.166827] BUG: using smp_processor_id() in preemptible [00000000] code: modprobe/6998 > [ 449.166848] caller is op_nmi_init+0xf0/0x2b0 [oprofile] > [ 449.166855] Pid: 6998, comm: modprobe Not tainted 2.6.27-rc5-mm1 #29 > [ 449.166860] Call Trace: > [ 449.166872] [] debug_smp_processor_id+0xd7/0xe0 > [ 449.166887] [] op_nmi_init+0xf0/0x2b0 [oprofile] > [ 449.166902] [] oprofile_init+0x0/0x60 [oprofile] > [ 449.166915] [] oprofile_arch_init+0x9/0x30 [oprofile] > [ 449.166928] [] oprofile_init+0x1e/0x60 [oprofile] > [ 449.166937] [] _stext+0x3b/0x160 > [ 449.166946] [] __mutex_unlock_slowpath+0xe5/0x190 > [ 449.166955] [] trace_hardirqs_on_caller+0xca/0x140 > [ 449.166965] [] sys_init_module+0xdc/0x210 > [ 449.166972] [] system_call_fastpath+0x16/0x1b > > Signed-off-by: Andrea Righi > Acked-by: Robert Richter > Signed-off-by: Ingo Molnar > --- > arch/x86/oprofile/nmi_int.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c > index fb4902b..4108d02 100644 > --- a/arch/x86/oprofile/nmi_int.c > +++ b/arch/x86/oprofile/nmi_int.c > @@ -551,7 +551,7 @@ int __init op_nmi_init(struct oprofile_operations *ops) > } > > /* default values, can be overwritten by model */ > - __get_cpu_var(switch_index) = 0; > + __raw_get_cpu_var(switch_index) = 0; > ops->create_files = nmi_create_files; > ops->setup = nmi_setup; > ops->shutdown = nmi_shutdown;