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From: <Nicolas.Ferre@microchip.com>
To: <ztong0001@gmail.com>, <Claudiu.Beznea@microchip.com>,
	<davem@davemloft.net>, <kuba@kernel.org>,
	<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1] net: macb: fix use after free on rmmod
Date: Wed, 8 Sep 2021 07:27:03 +0000	[thread overview]
Message-ID: <48b53487-a708-ec79-a993-3448f4ca6e6d@microchip.com> (raw)
In-Reply-To: <20210907202958.692166-1-ztong0001@gmail.com>

On 07/09/2021 at 22:29, Tong Zhang wrote:
> plat_dev->dev->platform_data is released by platform_device_unregister(),
> use of pclk and hclk is use after free. This patch keeps a copy to fix
> the issue.
> 
> [   31.261225] BUG: KASAN: use-after-free in macb_remove+0x77/0xc6 [macb_pci]
> [   31.275563] Freed by task 306:
> [   30.276782]  platform_device_release+0x25/0x80
> 
> Signed-off-by: Tong Zhang <ztong0001@gmail.com>
> ---
>   drivers/net/ethernet/cadence/macb_pci.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb_pci.c b/drivers/net/ethernet/cadence/macb_pci.c
> index 8b7b59908a1a..4dd0cec2e542 100644
> --- a/drivers/net/ethernet/cadence/macb_pci.c
> +++ b/drivers/net/ethernet/cadence/macb_pci.c
> @@ -110,10 +110,12 @@ static void macb_remove(struct pci_dev *pdev)
>   {
>          struct platform_device *plat_dev = pci_get_drvdata(pdev);
>          struct macb_platform_data *plat_data = dev_get_platdata(&plat_dev->dev);
> +       struct clk *pclk = plat_data->pclk;
> +       struct clk *hclk = plat_data->hclk;
> 
>          platform_device_unregister(plat_dev);
> -       clk_unregister(plat_data->pclk);
> -       clk_unregister(plat_data->hclk);
> +       clk_unregister(pclk);
> +       clk_unregister(hclk);

NACK, I  would prefer that you switch lines and do clock clk unregister 
before: this way we avoid the problem and I think that you don't need 
clocks for unregistering the platform device anyway.

Please change accordingly or tell me what could go bad.

Regards,
   Nicolas


>   }
> 
>   static const struct pci_device_id dev_id_table[] = {
> --
> 2.25.1
> 


-- 
Nicolas Ferre

  reply	other threads:[~2021-09-08  7:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-07 20:29 Tong Zhang
2021-09-08  7:27 ` Nicolas.Ferre [this message]
2021-09-08 19:02   ` [PATCH v2] " Tong Zhang
2021-09-09  7:53     ` Nicolas Ferre
2021-09-09 10:00     ` patchwork-bot+netdevbpf
2021-09-08 19:02   ` [PATCH v1] " Tong Zhang

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