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SubjectRe: [PATCH] power: supply: da9150: Fix use after free bug in da9150_charger_remove due to race condition
Hi,

On Fri, Mar 10, 2023 at 02:10:36AM +0800, Zheng Wang wrote:
> In da9150_charger_probe, &charger->otg_work is bound with
> da9150_charger_otg_work. da9150_charger_otg_ncb may be
> called to start the work.
>
> If we remove the module which will call da9150_charger_remove
> to make cleanup, there may be a unfinished work. The possible
> sequence is as follows:
>
> Fix it by canceling the work before cleanup in the mtk_jpeg_remove

mtk_jpeg_remove?

>
> CPU0 CPUc1
>
> |da9150_charger_otg_work
> da9150_charger_remove |
> power_supply_unregister |
> device_unregister |
> power_supply_dev_release|
> kfree(psy) |
> |
> | power_supply_changed(charger->usb);
> | //use
> Fixes: c1a281e34dae ("power: Add support for DA9150 Charger")
> Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
> ---

Looks correct to me, but the cancel_work_sync should happen after
usb_unregister_notifier(), otherwise there is still a race
condition.

-- Sebastian

> drivers/power/supply/da9150-charger.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/power/supply/da9150-charger.c b/drivers/power/supply/da9150-charger.c
> index 14da5c595dd9..41b68f2f6ed8 100644
> --- a/drivers/power/supply/da9150-charger.c
> +++ b/drivers/power/supply/da9150-charger.c
> @@ -642,6 +642,7 @@ static int da9150_charger_remove(struct platform_device *pdev)
> struct da9150_charger *charger = platform_get_drvdata(pdev);
> int irq;
>
> + cancel_work_sync(&charger->otg_work);
> /* Make sure IRQs are released before unregistering power supplies */
> irq = platform_get_irq_byname(pdev, "CHG_VBUS");
> free_irq(irq, charger);
> --
> 2.25.1
>
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