[RFT PATCH v2 1/2] compal-laptop: Fix leaking hwmon device

[RFT PATCH v2 1/2] compal-laptop: Fix leaking hwmon device

[Krzysztof Kozlowski]

The commit c2be45f09bb0 ("compal-laptop: Use
devm_hwmon_device_register_with_groups") wanted to change the
registering of hwmon device to resource-managed version. It mostly did
it except the main thing - it forgot to use devm-like function so the
hwmon device leaked after device removal or probe failure.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Fixes: c2be45f09bb0 ("compal-laptop: Use devm_hwmon_device_register_with_groups")
Cc: <stable@vger.kernel.org>

---
Changes since v1:
1. New patch.
---
 drivers/platform/x86/compal-laptop.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/compal-laptop.c b/drivers/platform/x86/compal-laptop.c
index 15c0fab2bfa1..eb9885e7fb0e 100644
--- a/drivers/platform/x86/compal-laptop.c
+++ b/drivers/platform/x86/compal-laptop.c
@@ -1026,9 +1026,9 @@ static int compal_probe(struct platform_device *pdev)
 	if (err)
 		return err;
 
-	hwmon_dev = hwmon_device_register_with_groups(&pdev->dev,
-						      "compal", data,
-						      compal_hwmon_groups);
+	hwmon_dev = devm_hwmon_device_register_with_groups(&pdev->dev,
+							   "compal", data,
+							   compal_hwmon_groups);
 	if (IS_ERR(hwmon_dev)) {
 		err = PTR_ERR(hwmon_dev);
 		goto remove;
-- 
1.9.1

[RFT PATCH v2 2/2] compal-laptop: Check return value of power_supply_register

[Krzysztof Kozlowski]

The return value of power_supply_register() call was not checked and
even on error probe() function returned 0. If registering failed then
during unbind the driver tried to unregister power supply which was not
actually registered.

This could lead to memory corruption because power_supply_unregister()
unconditionally cleans up given power supply.

Fix this by checking return status of power_supply_register() call. In
case of failure, clean up sysfs entries and fail the probe.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Fixes: 9be0fcb5ed46 ("compal-laptop: add JHL90, battery & hwmon interface")
Cc: <stable@vger.kernel.org>

---
Changes since v1:
1. Don't unregister hwmon device because previous patch solves this by
   using devm-like function.
---
 drivers/platform/x86/compal-laptop.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/compal-laptop.c b/drivers/platform/x86/compal-laptop.c
index eb9885e7fb0e..8455d50a5639 100644
--- a/drivers/platform/x86/compal-laptop.c
+++ b/drivers/platform/x86/compal-laptop.c
@@ -1036,7 +1036,9 @@ static int compal_probe(struct platform_device *pdev)
 
 	/* Power supply */
 	initialize_power_supply_data(data);
-	power_supply_register(&compal_device->dev, &data->psy);
+	err = power_supply_register(&compal_device->dev, &data->psy);
+	if (err < 0)
+		goto remove;
 
 	platform_set_drvdata(pdev, data);
 
@@ -1072,6 +1074,7 @@ static int compal_remove(struct platform_device *pdev)
 
 	data = platform_get_drvdata(pdev);
 	power_supply_unregister(&data->psy);
+	/* FIXME: missing hwmon_device_unregister() */
 
 	sysfs_remove_group(&pdev->dev.kobj, &compal_platform_attr_group);
 
-- 
1.9.1

Re: [RFT PATCH v2 2/2] compal-laptop: Check return value of power_supply_register

[Krzysztof Kozlowski]

On pią, 2015-02-20 at 14:04 +0100, Krzysztof Kozlowski wrote:
> The return value of power_supply_register() call was not checked and
> even on error probe() function returned 0. If registering failed then
> during unbind the driver tried to unregister power supply which was not
> actually registered.
> 
> This could lead to memory corruption because power_supply_unregister()
> unconditionally cleans up given power supply.
> 
> Fix this by checking return status of power_supply_register() call. In
> case of failure, clean up sysfs entries and fail the probe.
> 

(...)

>  
> @@ -1072,6 +1074,7 @@ static int compal_remove(struct platform_device *pdev)
>  
>  	data = platform_get_drvdata(pdev);
>  	power_supply_unregister(&data->psy);
> +	/* FIXME: missing hwmon_device_unregister() */
>  
>  	sysfs_remove_group(&pdev->dev.kobj, &compal_platform_attr_group);


Crap, I forgot to remove the FIXME note. It is no longer needed because
patch 1 fixes this.

I'll resend. Sorry for the noise.