linux-kernel - Re: [PATCH v3 5/5] acpi_processor: do not mark present at boot but not onlined CPU as onlined

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <3026804.eniy6FZ71k@vostro.rjw.lan>
Date:	Tue, 15 Apr 2014 07:43 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Igor Mammedov <imammedo@...hat.com>
Cc:	linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, x86@...nel.org, bp@...e.de,
	paul.gortmaker@...driver.com, JBeulich@...e.com, prarit@...hat.com,
	drjones@...hat.com, toshi.kani@...com, riel@...hat.com,
	gong.chen@...ux.intel.com, andi@...stfloor.org, lenb@...nel.org,
	linux-acpi@...r.kernel.org
Subject: Re: [PATCH v3 5/5] acpi_processor: do not mark present at boot but not onlined CPU as onlined

On Thursday, April 10, 2014 07:14:21 PM 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.

What do you mean by that?  What *exactly* is the failure scenario?

> 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 <imammedo@...hat.com>
> ---
>  drivers/acpi/acpi_processor.c |    3 ---
>  1 files changed, 0 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index c29c2c3..d56e4b4 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -403,9 +403,6 @@ static int acpi_processor_add(struct acpi_device *device,
>  	if (result)
>  		goto err;
>  
> -	pr->dev = dev;

The line above has to stay as is.

> -	dev->offline = pr->flags.need_hotplug_init;
> -
>  	/* Trigger the processor driver's .probe() if present. */
>  	if (device_attach(dev) >= 0)
>  		return 1;
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/