Subject: Re: [PATCH net] net: ravb: Fix possible UAF bug in ravb_remove
To:     Zheng Wang <zyytlz.wz@163.com>, <s.shtylyov@omp.ru>
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:   Yunsheng Lin <linyunsheng@huawei.com>
Message-ID: <cca0b40b-d6f8-54c7-1e46-83cb62d0a2f1@huawei.com>
Date:   Fri, 10 Mar 2023 09:12:37 +0800
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On 2023/3/9 18:02, 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

ther -> there

> after free bug on ndev.
> 
> Fix it by finishing the job before cleanup in ravb_remove.
> 
> Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
> Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
> ---
>  drivers/net/ethernet/renesas/ravb_main.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> 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);

As your previous patch, I still do not see anything stopping
dev_watchdog() from calling dev->netdev_ops->ndo_tx_timeout
after cancel_work_sync(), maybe I missed something obvious
here?


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