[PATCH] net: mvneta: bm: fix device reference leak on failed lookup

[PATCH] net: mvneta: bm: fix device reference leak on failed lookup

[Johan Hovold]

Make sure to drop the reference taken to the buffer manager device when
attempting to look up its driver data before the driver has been bound.

Note that holding a reference to a device does not prevent its driver
data from going away.

Fixes: 965cbbec7f20 ("net: mvneta: remove data pointer usage from device_node structure")
Cc: stable@vger.kernel.org	# 4.19
Cc: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/net/ethernet/marvell/mvneta_bm.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvneta_bm.c b/drivers/net/ethernet/marvell/mvneta_bm.c
index 6bb380494919..128fe1f512b4 100644
--- a/drivers/net/ethernet/marvell/mvneta_bm.c
+++ b/drivers/net/ethernet/marvell/mvneta_bm.c
@@ -395,9 +395,20 @@ static void mvneta_bm_put_sram(struct mvneta_bm *priv)
 
 struct mvneta_bm *mvneta_bm_get(struct device_node *node)
 {
-	struct platform_device *pdev = of_find_device_by_node(node);
+	struct platform_device *pdev;
+	struct mvneta_bm *priv;
+
+	pdev = of_find_device_by_node(node);
+	if (!pdev)
+		return NULL;
+
+	priv = platform_get_drvdata(pdev);
+	if (!priv) {
+		platform_device_put(pdev);
+		return NULL;
+	}
 
-	return pdev ? platform_get_drvdata(pdev) : NULL;
+	return priv;
 }
 EXPORT_SYMBOL_GPL(mvneta_bm_get);
 
-- 
2.54.0

Re: [PATCH] net: mvneta: bm: fix device reference leak on failed lookup

[Harshitha Ramamurthy]

On Thu, Jul 9, 2026 at 1:32 AM Johan Hovold <johan@kernel.org> wrote:
>
> Make sure to drop the reference taken to the buffer manager device when
> attempting to look up its driver data before the driver has been bound.
>
> Note that holding a reference to a device does not prevent its driver
> data from going away.
>
> Fixes: 965cbbec7f20 ("net: mvneta: remove data pointer usage from device_node structure")
> Cc: stable@vger.kernel.org      # 4.19
> Cc: Gregory CLEMENT <gregory.clement@bootlin.com>
> Signed-off-by: Johan Hovold <johan@kernel.org>

Okay, platform_device_put() has to be called directly instead of
mvneta_bm_put() because that takes in the priv structure.

Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>

> ---
>  drivers/net/ethernet/marvell/mvneta_bm.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/marvell/mvneta_bm.c b/drivers/net/ethernet/marvell/mvneta_bm.c
> index 6bb380494919..128fe1f512b4 100644
> --- a/drivers/net/ethernet/marvell/mvneta_bm.c
> +++ b/drivers/net/ethernet/marvell/mvneta_bm.c
> @@ -395,9 +395,20 @@ static void mvneta_bm_put_sram(struct mvneta_bm *priv)
>
>  struct mvneta_bm *mvneta_bm_get(struct device_node *node)
>  {
> -       struct platform_device *pdev = of_find_device_by_node(node);
> +       struct platform_device *pdev;
> +       struct mvneta_bm *priv;
> +
> +       pdev = of_find_device_by_node(node);
> +       if (!pdev)
> +               return NULL;
> +
> +       priv = platform_get_drvdata(pdev);
> +       if (!priv) {
> +               platform_device_put(pdev);
> +               return NULL;
> +       }
>
> -       return pdev ? platform_get_drvdata(pdev) : NULL;
> +       return priv;
>  }
>  EXPORT_SYMBOL_GPL(mvneta_bm_get);
>
> --
> 2.54.0
>
>