Re: [PATCH v2] power: supply: ds2782: fix possible use-after-free on remove

From: Sebastian Reichel
Date: Tue Feb 12 2019 - 17:30:32 EST


Hi,

On Tue, Feb 12, 2019 at 11:21:49AM -0500, Sven Van Asbroeck wrote:
> In remove(), use cancel_delayed_work_sync() to cancel the
> delayed work. Otherwise there's a chance that this work
> will continue to run until after the device has been removed.
>
> While we're here, fix the deallocation order in remove(),
> to correspond to the inverse of the probe() allocation
> order. This guarantees that any remaining work can run
> to completion with all driver structures still intact.
>
> This issue was detected with the help of Coccinelle.
>
> Signed-off-by: Sven Van Asbroeck <TheSven73@xxxxxxxxx>
> ---

Thanks, queued to power-supply's linux-next branch.

-- Sebastian

> v2: fix silly use-after-free in remove()
>
> drivers/power/supply/ds2782_battery.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/power/supply/ds2782_battery.c b/drivers/power/supply/ds2782_battery.c
> index 019c58493e3d..04b0fe7d7d62 100644
> --- a/drivers/power/supply/ds2782_battery.c
> +++ b/drivers/power/supply/ds2782_battery.c
> @@ -319,17 +319,17 @@ static void ds278x_power_supply_init(struct power_supply_desc *battery)
> static int ds278x_battery_remove(struct i2c_client *client)
> {
> struct ds278x_info *info = i2c_get_clientdata(client);
> + int id = info->id;
>
> power_supply_unregister(info->battery);
> + cancel_delayed_work_sync(&info->bat_work);
> kfree(info->battery_desc.name);
> + kfree(info);
>
> mutex_lock(&battery_lock);
> - idr_remove(&battery_id, info->id);
> + idr_remove(&battery_id, id);
> mutex_unlock(&battery_lock);
>
> - cancel_delayed_work(&info->bat_work);
> -
> - kfree(info);
> return 0;
> }
>
> --
> 2.17.1
>

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