Subject: Re: [PATCH net] net: ravb: Fix possible UAF bug in ravb_remove
To:     Zheng Wang <zyytlz.wz@163.com>
CC:     <davem@davemloft.net>, <edumazet@google.com>, <kuba@kernel.org>,
        <pabeni@redhat.com>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <hackerzheng666@gmail.com>,
        <1395428693sheep@gmail.com>, <alex000young@gmail.com>
References: <20230309100248.3831498-1-zyytlz.wz@163.com>
From:   Sergey Shtylyov <s.shtylyov@omp.ru>
Organization: Open Mobile Platform
Message-ID: <9054b170-8ed2-445c-6150-82f98af5808b@omp.ru>
Date:   Thu, 9 Mar 2023 18:47:27 +0300
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Hello!

On 3/9/23 1:02 PM, Zheng Wang wrote:

> In ravb_probe, priv->work was bound with ravb_tx_timeout_work.
> If timeout occurs, it will start the work. And if we call
> ravb_remove without finishing the work, ther may be a use
> after free bug on ndev.

   Have you actually encountered it?

> Fix it by finishing the job before cleanup in ravb_remove.
> 
> Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")

   Hm... sorry about that. :-)

> Signed-off-by: Zheng Wang <zyytlz.wz@163.com>

Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>

[...]
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index 0f54849a3823..07a08e72f440 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -2892,6 +2892,7 @@ static int ravb_remove(struct platform_device *pdev)
>  	struct ravb_private *priv = netdev_priv(ndev);
>  	const struct ravb_hw_info *info = priv->info;
>  
> +	cancel_work_sync(&priv->work);

   I think we need an empty line here...

>  	/* Stop PTP Clock driver */
>  	if (info->ccc_gac)
>  		ravb_ptp_stop(ndev);

MBR, Sergey