From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH] ACPI/hotplug: Fix STARTING/DYING action in acpi_cpu_soft_notify() Date: Tue, 20 May 2014 00:55:51 +0200 Message-ID: <2011129.WMiXDPUasW@vostro.rjw.lan> References: <1399557539-7282-1-git-send-email-toshi.kani@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Return-path: Received: from v094114.home.net.pl ([79.96.170.134]:62986 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751707AbaESWi5 (ORCPT ); Mon, 19 May 2014 18:38:57 -0400 In-Reply-To: <1399557539-7282-1-git-send-email-toshi.kani@hp.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Toshi Kani Cc: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org On Thursday, May 08, 2014 07:58:59 AM Toshi Kani wrote: > During CPU online/offline testing on a large system, one of the > processors got stuck after the message "bad: scheduling from the > idle thread!". The problem is that acpi_cpu_soft_notify() calls > acpi_bus_get_device() for all action types. CPU_STARTING and > CPU_DYING do not allow the notify handlers to sleep. However, > acpi_bus_get_device() can sleep in acpi_ut_acquire_mutex(). > > Change acpi_cpu_soft_notify() to return immediately for CPU_STARTING > and CPU_DYING as they have no action in this handler. > > Signed-off-by: Toshi Kani Queued up for 3.16, thanks! > --- > drivers/acpi/processor_driver.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c > index 7f70f31..4fcbd67 100644 > --- a/drivers/acpi/processor_driver.c > +++ b/drivers/acpi/processor_driver.c > @@ -121,6 +121,13 @@ static int acpi_cpu_soft_notify(struct notifier_block *nfb, > struct acpi_processor *pr = per_cpu(processors, cpu); > struct acpi_device *device; > > + /* > + * CPU_STARTING and CPU_DYING must not sleep. Return here since > + * acpi_bus_get_device() may sleep. > + */ > + if (action == CPU_STARTING || action == CPU_DYING) > + return NOTIFY_DONE; > + > if (!pr || acpi_bus_get_device(pr->handle, &device)) > return NOTIFY_DONE; > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.