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Sender: Guenter Roeck <groeck7@gmail.com>
Message-ID: <29536273-4cd5-5530-083a-c8b8e42e1eb1@roeck-us.net>
Date:   Thu, 13 Oct 2022 06:53:10 -0700
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Subject: Re: [PATCH] drivers: watchdog: exar_wdt.c fix use after free
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To:     Manank Patel <pmanank200502@gmail.com>
Cc:     linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20221013095439.1425108-1-pmanank200502@gmail.com>
From:   Guenter Roeck <linux@roeck-us.net>
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On 10/13/22 02:54, Manank Patel wrote:
> fix use after free by storing the result of PTR_ERR(n->pdev)
> to a local variable before returning.
> 
> Signed-off-by: Manank Patel <pmanank200502@gmail.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>   drivers/watchdog/exar_wdt.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/exar_wdt.c b/drivers/watchdog/exar_wdt.c
> index 35058d8b21bc..7c61ff343271 100644
> --- a/drivers/watchdog/exar_wdt.c
> +++ b/drivers/watchdog/exar_wdt.c
> @@ -355,8 +355,10 @@ static int __init exar_wdt_register(struct wdt_priv *priv, const int idx)
>   						    &priv->wdt_res, 1,
>   						    priv, sizeof(*priv));
>   	if (IS_ERR(n->pdev)) {
> +		int err = PTR_ERR(n->pdev);
> +
>   		kfree(n);
> -		return PTR_ERR(n->pdev);
> +		return err;
>   	}
>   
>   	list_add_tail(&n->list, &pdev_list);