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    Subject[PATCH 4.19 17/48] leds: lm3533: fix use-after-free on unbind
    Date
    From: Johan Hovold <johan@kernel.org>

    commit d584221e683bbd173738603b83a315f27d27d043 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: 50154e29e5cc ("leds: lm3533: 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>

    ---
    drivers/leds/leds-lm3533.c | 12 +++++++++---
    1 file changed, 9 insertions(+), 3 deletions(-)

    --- a/drivers/leds/leds-lm3533.c
    +++ b/drivers/leds/leds-lm3533.c
    @@ -698,7 +698,7 @@ static int lm3533_led_probe(struct platf

    platform_set_drvdata(pdev, led);

    - ret = devm_led_classdev_register(pdev->dev.parent, &led->cdev);
    + ret = led_classdev_register(pdev->dev.parent, &led->cdev);
    if (ret) {
    dev_err(&pdev->dev, "failed to register LED %d\n", pdev->id);
    return ret;
    @@ -708,13 +708,18 @@ static int lm3533_led_probe(struct platf

    ret = lm3533_led_setup(led, pdata);
    if (ret)
    - return ret;
    + goto err_deregister;

    ret = lm3533_ctrlbank_enable(&led->cb);
    if (ret)
    - return ret;
    + goto err_deregister;

    return 0;
    +
    +err_deregister:
    + led_classdev_unregister(&led->cdev);
    +
    + return ret;
    }

    static int lm3533_led_remove(struct platform_device *pdev)
    @@ -724,6 +729,7 @@ static int lm3533_led_remove(struct plat
    dev_dbg(&pdev->dev, "%s\n", __func__);

    lm3533_ctrlbank_disable(&led->cb);
    + led_classdev_unregister(&led->cdev);

    return 0;
    }

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