linux-kernel - Re: [PATCH] cpuidle: Check cpuidle driver before add refcount

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]

Message-ID: <2041584.4YznqfT0Od@vostro.rjw.lan>
Date:	Fri, 30 Aug 2013 14:01:02 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Daniel Fu <danifu@...dia.com>
Cc:	daniel.lezcano@...aro.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, joqiu@...dia.com
Subject: Re: [PATCH] cpuidle: Check cpuidle driver before add refcount

On Friday, August 30, 2013 07:48:22 PM Daniel Fu wrote:
> If the current CPU has no cpuidle driver, drv will be NULL.
> Check if we get drv successfully before add refount
> to prevent Kernel panic.

What is the actual scenario that may lead to this panic?

Rafael


> Signed-off-by: Daniel Fu <danifu@...dia.com>
> ---
>  drivers/cpuidle/driver.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
> index 3ac499d..6e11701 100644
> --- a/drivers/cpuidle/driver.c
> +++ b/drivers/cpuidle/driver.c
> @@ -331,7 +331,8 @@ struct cpuidle_driver *cpuidle_driver_ref(void)
>  	spin_lock(&cpuidle_driver_lock);
>  
>  	drv = cpuidle_get_driver();
> -	drv->refcnt++;
> +	if (drv)
> +		drv->refcnt++;
>  
>  	spin_unlock(&cpuidle_driver_lock);
>  	return drv;
> 
-- 
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/