Re: [PATCHv4 1/9] Thermal: Check for validity before doing kfree

[Zhang Rui]

On Wed, 2013-10-02 at 00:08 +0530, Durgadoss R wrote:
> The thermal_release function is called whenever
> any device belonging to 'thermal' class unregisters.
> This function performs kfree(cdev) without any check.
> In cases where there are more device registrations
> other than just 'thermal_zone' and 'cooling_device'
> this might accidently free memory allocated them
> silently; and cause memory errors.
> 
> This patch changes this behavior by doing
> kfree(cdev) only when the device pointer belongs
> to a real cdev i.e. cooling_device.
> 
> Signed-off-by: Durgadoss R <durgadoss.r@xxxxxxxxx>

applied to thermal -next.

thanks,
rui
> ---
>  drivers/thermal/thermal_core.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 1f02e8e..8c5131d 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -1280,7 +1280,8 @@ static void thermal_release(struct device *dev)
>  		     sizeof("thermal_zone") - 1)) {
>  		tz = to_thermal_zone(dev);
>  		kfree(tz);
> -	} else {
> +	} else if(!strncmp(dev_name(dev), "cooling_device",
> +			sizeof("cooling_device") - 1)){
>  		cdev = to_cooling_device(dev);
>  		kfree(cdev);
>  	}


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