linux-kernel - Re: [PATCH RFC] acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has

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

Date:	Tue, 28 Feb 2012 15:19:43 +0800
From:	Yong Zhang <yong.zhang0@...il.com>
To:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc:	deepthi@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
	lenb@...nel.org, linux-acpi@...r.kernel.org
Subject: Re: [PATCH RFC] acpi: Fix unprotected smp_processor_id() in
 acpi_processor_cst_has_changed()

On Thu, Feb 23, 2012 at 12:58:05PM -0800, Paul E. McKenney wrote:
> The acpi_processor_cst_has_changed() function is invoked from a
> CPU_ONLINE or CPU_DEAD function, which might well execute on CPU 0
> even though the CPU being hotplugged is some other CPU.  In addition,
> acpi_processor_cst_has_changed() invokes smp_processor_id() without
> protection, resulting in splats when onlining CPUs.
> 
> This commit therefore changes the smp_processor_id() to pr->id, as is
> used elsewhere in the code, for example, in acpi_processor_add().
> 
> This works for me, but I don't claim to understand ACPI.
> 
> Signed-off-by: Paul E. McKenney <paul.mckenney@...aro.org>

Got the same warning.
And the patch works on my side.

Tested-by: Yong Zhang <yong.zhang0@...il.com>

> 
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index 0e8e2de..9e57b06 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -1159,8 +1159,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr)
>  	 * to make the code that updates C-States be called once.
>  	 */
>  
> -	if (smp_processor_id() == 0 &&
> -			cpuidle_get_driver() == &acpi_idle_driver) {
> +	if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) {
>  
>  		cpuidle_pause_and_lock();
>  		/* Protect against cpu-hotplug */
> 
> --
> 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/

-- 
Only stand for myself
--
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/