[PATCH] net: ethernet: rtsn: Fix a null pointer dereference in rtsn_probe()

[PATCH] net: ethernet: rtsn: Fix a null pointer dereference in rtsn_probe()

[Haoxiang Li]

Add check for the return value of rcar_gen4_ptp_alloc()
to prevent potential null pointer dereference.

Fixes: b0d3969d2b4d ("net: ethernet: rtsn: Add support for Renesas Ethernet-TSN")
Cc: stable@vger.kernel.org
Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
---
 drivers/net/ethernet/renesas/rtsn.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/renesas/rtsn.c b/drivers/net/ethernet/renesas/rtsn.c
index 6b3f7fca8d15..f5df3374d279 100644
--- a/drivers/net/ethernet/renesas/rtsn.c
+++ b/drivers/net/ethernet/renesas/rtsn.c
@@ -1260,6 +1260,10 @@ static int rtsn_probe(struct platform_device *pdev)
 	priv->pdev = pdev;
 	priv->ndev = ndev;
 	priv->ptp_priv = rcar_gen4_ptp_alloc(pdev);
+	if (!priv->ptp_priv) {
+		ret = -ENOMEM;
+		goto error_free;
+	}
 
 	spin_lock_init(&priv->lock);
 	platform_set_drvdata(pdev, priv);
-- 
2.25.1

Re: [PATCH] net: ethernet: rtsn: Fix a null pointer dereference in rtsn_probe()

[Niklas Söderlund]

Hi Haoxiang,

Thanks for your fix, nice catch.

On 2025-05-24 15:58:25 +0800, Haoxiang Li wrote:
> Add check for the return value of rcar_gen4_ptp_alloc()
> to prevent potential null pointer dereference.
> 
> Fixes: b0d3969d2b4d ("net: ethernet: rtsn: Add support for Renesas Ethernet-TSN")
> Cc: stable@vger.kernel.org
> Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
> ---
>  drivers/net/ethernet/renesas/rtsn.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/net/ethernet/renesas/rtsn.c b/drivers/net/ethernet/renesas/rtsn.c
> index 6b3f7fca8d15..f5df3374d279 100644
> --- a/drivers/net/ethernet/renesas/rtsn.c
> +++ b/drivers/net/ethernet/renesas/rtsn.c
> @@ -1260,6 +1260,10 @@ static int rtsn_probe(struct platform_device *pdev)
>  	priv->pdev = pdev;
>  	priv->ndev = ndev;

nit: I would add a blank line here to make the grouping similar to the 
style of other error checks in probe.

With that fixed,

Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

>  	priv->ptp_priv = rcar_gen4_ptp_alloc(pdev);
> +	if (!priv->ptp_priv) {
> +		ret = -ENOMEM;
> +		goto error_free;
> +	}
>  
>  	spin_lock_init(&priv->lock);
>  	platform_set_drvdata(pdev, priv);
> -- 
> 2.25.1
> 

-- 
Kind Regards,
Niklas Söderlund

Re: [PATCH] net: ethernet: rtsn: Fix a null pointer dereference in rtsn_probe()

[Joe Damato]

On Sat, May 24, 2025 at 03:58:25PM +0800, Haoxiang Li wrote:
> Add check for the return value of rcar_gen4_ptp_alloc()
> to prevent potential null pointer dereference.

Was the null deref observed in the wild? Asking because I am
wondering if this is clean up instead of a Fixes ?

> Fixes: b0d3969d2b4d ("net: ethernet: rtsn: Add support for Renesas Ethernet-TSN")
> Cc: stable@vger.kernel.org
> Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
> ---
>  drivers/net/ethernet/renesas/rtsn.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/net/ethernet/renesas/rtsn.c b/drivers/net/ethernet/renesas/rtsn.c
> index 6b3f7fca8d15..f5df3374d279 100644
> --- a/drivers/net/ethernet/renesas/rtsn.c
> +++ b/drivers/net/ethernet/renesas/rtsn.c
> @@ -1260,6 +1260,10 @@ static int rtsn_probe(struct platform_device *pdev)
>  	priv->pdev = pdev;
>  	priv->ndev = ndev;
>  	priv->ptp_priv = rcar_gen4_ptp_alloc(pdev);
> +	if (!priv->ptp_priv) {
> +		ret = -ENOMEM;
> +		goto error_free;
> +	}
>  
>  	spin_lock_init(&priv->lock);
>  	platform_set_drvdata(pdev, priv);
> -- 
> 2.25.1
> 
>