leds: 88pm860x: fix use-after-free on unbind

commit eca21c2d8655387823d695b26e6fe78cf3975c05 upstream.

Several MFD child drivers register their class devices directly under
the parent device. This means you cannot blindly do devres conversions
so that deregistration ends up being tied to the parent device,
something which leads to use-after-free on driver unbind when the class
device is released while still being registered.

Fixes: 375446df95ee ("leds: 88pm860x: Use devm_led_classdev_register")
Cc: stable <stable@vger.kernel.org>     # 4.6
Cc: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/leds/leds-88pm860x.c b/drivers/leds/leds-88pm860x.c
index 77a104d2b1243a503d8daa0660d73ae19baa819e..13f414ff6fd007748e18f3fbe1b46356e4e3fafd 100644 (file)
--- a/drivers/leds/leds-88pm860x.c
+++ b/drivers/leds/leds-88pm860x.c
@@ -207,21 +207,33 @@ static int pm860x_led_probe(struct platform_device *pdev)
        data->cdev.brightness_set_blocking = pm860x_led_set;
        mutex_init(&data->lock);
 
-       ret = devm_led_classdev_register(chip->dev, &data->cdev);
+       ret = led_classdev_register(chip->dev, &data->cdev);
        if (ret < 0) {
                dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
                return ret;
        }
        pm860x_led_set(&data->cdev, 0);
+
+       platform_set_drvdata(pdev, data);
+
        return 0;
 }
 
+static int pm860x_led_remove(struct platform_device *pdev)
+{
+       struct pm860x_led *data = platform_get_drvdata(pdev);
+
+       led_classdev_unregister(&data->cdev);
+
+       return 0;
+}
 
 static struct platform_driver pm860x_led_driver = {
        .driver = {
                .name   = "88pm860x-led",
        },
        .probe  = pm860x_led_probe,
+       .remove = pm860x_led_remove,
 };
 
 module_platform_driver(pm860x_led_driver);