[PATCH v2] hwmon: (gpio-fan) Fix fan_ctrl_init error path

[PATCH v2] hwmon: (gpio-fan) Fix fan_ctrl_init error path

[Axel Lin]

In current implementation, the sysfs entries is not removed before return -ENODEV.

Creating the sysfs attribute should be the last thing done by the function,
after all the rest has been successful.
Otherwise there is a small window during which user-space can access the attribute
but the driver isn't ready to deal with the requests.

Fix it by moving sysfs_create_group to be the last thing done by the function.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
---
 drivers/hwmon/gpio-fan.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c
index aa701a1..f141a1d 100644
--- a/drivers/hwmon/gpio-fan.c
+++ b/drivers/hwmon/gpio-fan.c
@@ -376,10 +376,6 @@ static int fan_ctrl_init(struct gpio_fan_data *fan_data,
 		}
 	}
 
-	err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
-	if (err)
-		goto err_free_gpio;
-
 	fan_data->num_ctrl = num_ctrl;
 	fan_data->ctrl = ctrl;
 	fan_data->num_speed = pdata->num_speed;
@@ -391,6 +387,10 @@ static int fan_ctrl_init(struct gpio_fan_data *fan_data,
 		goto err_free_gpio;
 	}
 
+	err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
+	if (err)
+		goto err_free_gpio;
+
 	return 0;
 
 err_free_gpio:
-- 
1.7.2

Re: [lm-sensors] [PATCH v2] hwmon: (gpio-fan) Fix fan_ctrl_init error path

[Simon Guinot]

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On Tue, Nov 09, 2010 at 04:41:48PM +0800, Axel Lin wrote:
> In current implementation, the sysfs entries is not removed before return -ENODEV.
> 
> Creating the sysfs attribute should be the last thing done by the function,
> after all the rest has been successful.
> Otherwise there is a small window during which user-space can access the attribute
> but the driver isn't ready to deal with the requests.
> 
> Fix it by moving sysfs_create_group to be the last thing done by the function.
> 
> Signed-off-by: Axel Lin <axel.lin@gmail.com>

Thanks for the patch.

Acked-by: Simon Guinot <sguinot@lacie.com>

> ---
>  drivers/hwmon/gpio-fan.c |    8 ++++----
>  1 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c
> index aa701a1..f141a1d 100644
> --- a/drivers/hwmon/gpio-fan.c
> +++ b/drivers/hwmon/gpio-fan.c
> @@ -376,10 +376,6 @@ static int fan_ctrl_init(struct gpio_fan_data *fan_data,
>  		}
>  	}
>  
> -	err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
> -	if (err)
> -		goto err_free_gpio;
> -
>  	fan_data->num_ctrl = num_ctrl;
>  	fan_data->ctrl = ctrl;
>  	fan_data->num_speed = pdata->num_speed;
> @@ -391,6 +387,10 @@ static int fan_ctrl_init(struct gpio_fan_data *fan_data,
>  		goto err_free_gpio;
>  	}
>  
> +	err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
> +	if (err)
> +		goto err_free_gpio;
> +
>  	return 0;
>  
>  err_free_gpio:
> -- 
> 1.7.2
> 
> 
> 
> 
> _______________________________________________
> lm-sensors mailing list
> lm-sensors@lm-sensors.org
> http://lists.lm-sensors.org/mailman/listinfo/lm-sensors

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Re: [PATCH v2] hwmon: (gpio-fan) Fix fan_ctrl_init error path

[Guenter Roeck]

On Tue, 2010-11-09 at 03:41 -0500, Axel Lin wrote:
> In current implementation, the sysfs entries is not removed before return -ENODEV.
> 
> Creating the sysfs attribute should be the last thing done by the function,
> after all the rest has been successful.
> Otherwise there is a small window during which user-space can access the attribute
> but the driver isn't ready to deal with the requests.
> 
> Fix it by moving sysfs_create_group to be the last thing done by the function.
> 
> Signed-off-by: Axel Lin <axel.lin@gmail.com>

Applied.

Thanks,
Guenter