From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759340AbaD3Vej (ORCPT ); Wed, 30 Apr 2014 17:34:39 -0400 Received: from g9t1613g.houston.hp.com ([15.240.0.71]:33255 "EHLO g9t1613g.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752334AbaD3Veh (ORCPT ); Wed, 30 Apr 2014 17:34:37 -0400 Message-ID: <1398893151.1789.46.camel@misato.fc.hp.com> Subject: Re: [PATCH v4 3/5] acpi_processor: do not mark present at boot but not onlined CPU as onlined From: Toshi Kani To: Igor Mammedov Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, bp@suse.de, paul.gortmaker@windriver.com, JBeulich@suse.com, prarit@redhat.com, drjones@redhat.com, riel@redhat.com, gong.chen@linux.intel.com, andi@firstfloor.org, lenb@kernel.org, rjw@rjwysocki.net, linux-acpi@vger.kernel.org Date: Wed, 30 Apr 2014 15:25:51 -0600 In-Reply-To: <1397488277-14865-4-git-send-email-imammedo@redhat.com> References: <1397488277-14865-1-git-send-email-imammedo@redhat.com> <1397488277-14865-4-git-send-email-imammedo@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.8.5 (3.8.5-2.fc19) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2014-04-14 at 17:11 +0200, Igor Mammedov wrote: > acpi_processor_add() assumes that present at boot CPUs > are always onlined, it is not so if a CPU failed to become > onlined. As result acpi_processor_add() will mark such CPU > device as onlined in sysfs and following attempts to > online/offline it using /sys/device/system/cpu/cpuX/online > attribute will fail. > > Do not poke into device internals in acpi_processor_add() > and touch "struct device { .offline }" attribute, since > for CPUs onlined at boot it's set by: > topology_init() -> arch_register_cpu() -> register_cpu() > before ACPI device tree is parsed, and for hotplugged > CPUs it's set when userspace onlines CPU via sysfs. > > Signed-off-by: Igor Mammedov > --- > v2: > - fix regression in v1 leading to NULL pointer dereference > on CPU unplug, do not remove "pr->dev = dev;" > --- > drivers/acpi/acpi_processor.c | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c > index c29c2c3..42d66f8 100644 > --- a/drivers/acpi/acpi_processor.c > +++ b/drivers/acpi/acpi_processor.c > @@ -404,7 +404,6 @@ static int acpi_processor_add(struct acpi_device *device, > goto err; > > pr->dev = dev; > - dev->offline = pr->flags.need_hotplug_init; IIRC, this change was necessary to handle the case when maxcpus=X is specified at boot. In this case, excessive CPU's dev->offline needs to be set to 1. Can you verify this? Thanks, -Toshi