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 b3044c9a8120f01077d6d8cdc4179d682ae6774d..465c3755cf2e4a7844cc979f288d8538c56f41fa 100644 (file)
--- a/drivers/leds/leds-88pm860x.c
+++ b/drivers/leds/leds-88pm860x.c
@@ -203,21 +203,33 @@ 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);