[PATCH 3.13.y-ckt 72/95] compal-laptop: Check return value of power_supply_register

[Kamal Mostafa]

3.13.11-ckt21 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Krzysztof Kozlowski <k.kozlowski at samsung.com>

commit 1915a718b1872edffcb13e5436a9f7302d3d36f0 upstream.

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 at samsung.com>
Fixes: 9be0fcb5ed46 ("compal-laptop: add JHL90, battery & hwmon interface")
Signed-off-by: Sebastian Reichel <sre at kernel.org>
Signed-off-by: Jiri Slaby <jslaby at suse.cz> [backport to 3.12]
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/platform/x86/compal-laptop.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/compal-laptop.c b/drivers/platform/x86/compal-laptop.c
index eaa78ed..b978cd3 100644
--- a/drivers/platform/x86/compal-laptop.c
+++ b/drivers/platform/x86/compal-laptop.c
@@ -1049,7 +1049,13 @@ 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) {
+		hwmon_device_unregister(data->hwmon_dev);
+		sysfs_remove_group(&pdev->dev.kobj, &compal_attribute_group);
+		kfree(data);
+		return err;
+	}
 
 	platform_set_drvdata(pdev, data);
 
-- 
1.9.1