Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1945940Ab2JSQkx (ORCPT ); Fri, 19 Oct 2012 12:40:53 -0400 Received: from mail.x86-64.org ([217.9.48.20]:37056 "EHLO mail.x86-64.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964795Ab2JSQkt (ORCPT ); Fri, 19 Oct 2012 12:40:49 -0400 Date: Fri, 19 Oct 2012 18:40:45 +0200 From: Borislav Petkov To: Tang Chen Cc: stable@vger.kernel.org, tony.luck@intel.com, bp@amd64.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, miaox@cn.fujitsu.com, laijs@cn.fujitsu.com, wency@cn.fujitsu.com, x86@kernel.org, linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org, Borislav Petkov Subject: Re: [PATCH v2 1/2] Replace if statement with WARN_ON_ONCE() in cmci_rediscover(). Message-ID: <20121019164045.GE11958@aftab.osrc.amd.com> References: <1350625528-1385-1-git-send-email-tangchen@cn.fujitsu.com> <1350625528-1385-2-git-send-email-tangchen@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1350625528-1385-2-git-send-email-tangchen@cn.fujitsu.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1567 Lines: 45 On Fri, Oct 19, 2012 at 01:45:27PM +0800, Tang Chen wrote: > cmci_rediscover() is only called by the CPU_POST_DEAD event handler, > which means the corresponding cpu has already dead. As a result, it > won't be accessed in the for_each_online_cpu loop. > So, we could change the if(cpu == dying) statement into a WARN_ON_ONCE(). > > Signed-off-by: Tang Chen > --- > arch/x86/kernel/cpu/mcheck/mce_intel.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/cpu/mcheck/mce_intel.c b/arch/x86/kernel/cpu/mcheck/mce_intel.c > index 38e49bc..481d152 100644 > --- a/arch/x86/kernel/cpu/mcheck/mce_intel.c > +++ b/arch/x86/kernel/cpu/mcheck/mce_intel.c > @@ -180,8 +180,8 @@ void cmci_rediscover(int dying) > cpumask_copy(old, ¤t->cpus_allowed); > > for_each_online_cpu(cpu) { > - if (cpu == dying) > - continue; > + WARN_ON_ONCE(cpu == dying); Ok, I don't understand that: we want to warn that the rediscovering is happening on a dying cpu?? And before that, we simply jumped over it and didn't do the rediscovering there? Why should we warn at all? Huh? -- Regards/Gruss, Boris. Advanced Micro Devices GmbH Einsteinring 24, 85609 Dornach GM: Alberto Bozzo Reg: Dornach, Landkreis Muenchen HRB Nr. 43632 WEEE Registernr: 129 19551 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/