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References: <20220416073721.3954-1-linmq006@gmail.com>
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From:   Benjamin Tissoires <benjamin.tissoires@redhat.com>
Date:   Thu, 21 Apr 2022 11:19:27 +0200
Message-ID: <CAO-hwJJyrPUdOm6JuzbE4Hi4pYi6hZDhf8zkJoczeOwj5jeaaA@mail.gmail.com>
Subject: Re: [PATCH] HID: elan: Fix potential double free in elan_input_configured
To:     Miaoqian Lin <linmq006@gmail.com>
Cc:     Jiri Kosina <jikos@kernel.org>,
        Dinghao Liu <dinghao.liu@zju.edu.cn>,
        Alexandrov Stansilav <neko@nya.ai>,
        linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
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On Sat, Apr 16, 2022 at 9:37 AM Miaoqian Lin <linmq006@gmail.com> wrote:
>
> 'input' is a managed resource allocated with devm_input_allocate_device(),
> so there is no need to call input_free_device() explicitly or
> there will be a double free.
>
> According to the doc of devm_input_allocate_device():
>  * Managed input devices do not need to be explicitly unregistered or
>  * freed as it will be done automatically when owner device unbinds from
>  * its driver (or binding fails).
>
> Fixes: b7429ea53d6c ("HID: elan: Fix memleak in elan_input_configured")
> Fixes: 9a6a4193d65b ("HID: Add driver for USB ELAN Touchpad")
> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>

Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Thanks for the patch!

Cheers,
Benjamin

> ---
>  drivers/hid/hid-elan.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/drivers/hid/hid-elan.c b/drivers/hid/hid-elan.c
> index 3091355d48df..8e4a5528e25d 100644
> --- a/drivers/hid/hid-elan.c
> +++ b/drivers/hid/hid-elan.c
> @@ -188,7 +188,6 @@ static int elan_input_configured(struct hid_device *hdev, struct hid_input *hi)
>         ret = input_mt_init_slots(input, ELAN_MAX_FINGERS, INPUT_MT_POINTER);
>         if (ret) {
>                 hid_err(hdev, "Failed to init elan MT slots: %d\n", ret);
> -               input_free_device(input);
>                 return ret;
>         }
>
> @@ -200,7 +199,6 @@ static int elan_input_configured(struct hid_device *hdev, struct hid_input *hi)
>                 hid_err(hdev, "Failed to register elan input device: %d\n",
>                         ret);
>                 input_mt_destroy_slots(input);
> -               input_free_device(input);
>                 return ret;
>         }
>
> --
> 2.17.1
>