From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752827AbYIVK3Q (ORCPT ); Mon, 22 Sep 2008 06:29:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751841AbYIVK3A (ORCPT ); Mon, 22 Sep 2008 06:29:00 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:45691 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751497AbYIVK3A (ORCPT ); Mon, 22 Sep 2008 06:29:00 -0400 Date: Mon, 22 Sep 2008 12:28:34 +0200 From: Ingo Molnar To: Andrea Righi 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 Message-ID: <20080922102834.GA32692@elte.hu> References: <1221908320-7183-1-git-send-email-righi.andrea@gmail.com> <20080922102524.GB30137@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080922102524.GB30137@elte.hu> 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 * 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 ------------> >>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;