From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935905Ab1JFWNk (ORCPT ); Thu, 6 Oct 2011 18:13:40 -0400 Received: from mail-iy0-f174.google.com ([209.85.210.174]:42608 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935612Ab1JFWNj (ORCPT ); Thu, 6 Oct 2011 18:13:39 -0400 Date: Thu, 6 Oct 2011 15:13:34 -0700 From: Tejun Heo To: "Srivatsa S. Bhat" Cc: Borislav Petkov , "Rafael J. Wysocki" , Borislav Petkov , "tigran@aivazian.fsnet.co.uk" , "tglx@linutronix.de" , "mingo@elte.hu" , "hpa@zytor.com" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , Linux PM mailing list Subject: Re: [BUGFIX][PATCH RESEND] Freezer, CPU hotplug, x86 Microcode: Fix task freezing failures Message-ID: <20111006221334.GB7085@google.com> References: <20111002195023.GC31799@mtj.dyndns.org> <201110052226.58373.rjw@sisk.pl> <4E8CC8FA.2090100@linux.vnet.ibm.com> <201110060043.19583.rjw@sisk.pl> <4E8D4FC6.1080204@linux.vnet.ibm.com> <20111006083439.GA21575@aftab> <4E8DCDA6.8030802@linux.vnet.ibm.com> <4E8E1125.4050701@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E8E1125.4050701@linux.vnet.ibm.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Fri, Oct 07, 2011 at 02:05:49AM +0530, Srivatsa S. Bhat wrote: ... > diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c > index f924280..cd7ef2f 100644 > --- a/arch/x86/kernel/microcode_core.c > +++ b/arch/x86/kernel/microcode_core.c > @@ -483,7 +483,15 @@ mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu) > sysfs_remove_group(&sys_dev->kobj, &mc_attr_group); > pr_debug("CPU%d removed\n", cpu); > break; > - case CPU_DEAD: > + > + /* > + * Do not invalidate the microcode if a CPU goes offline, > + * because it would be impossible to get the microcode again > + * from userspace when the CPU comes back up, if the userspace > + * happens to be frozen at that moment by the freezer subsystem, > + * for example, due to a suspend operation in progress. > + */ > + This still looks like a bandaid to me. The exclusion approach didn't pan out? Thank you. -- tejun