compal-laptop: Check return value of power_supply_register

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@samsung.com>
Fixes: 9be0fcb5ed46 ("compal-laptop: add JHL90, battery & hwmon interface")
Signed-off-by: Sebastian Reichel <sre@kernel.org>
[lizf: Backported to 3.4: there's no "remove" label. Do cleanup inside if block]
Signed-off-by: Zefan Li <lizefan@huawei.com>

diff --git a/drivers/platform/x86/compal-laptop.c b/drivers/platform/x86/compal-laptop.c
index 1887e2f166a43edeb449ae2851c8f77a8a63bcfc..67938889f5b62965cb5ddf7c1052d1c2dffce46c 100644 (file)
--- a/drivers/platform/x86/compal-laptop.c
+++ b/drivers/platform/x86/compal-laptop.c
@@ -1047,7 +1047,13 @@ static int __devinit 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);
+       }
 
        platform_set_drvdata(pdev, data);