Re: [PATCH 17/23] net: mv643xx: use platform_device_set_of_node()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Directly assigning a `devm_kzalloc()` pointer to `pdev->dev.platform_data` leads to an invalid `kfree()` upon platform device release.
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commit 8b40f4373a03093beb86a0174e83ff04d8438e9e
Author: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

net: mv643xx: use platform_device_set_of_node()

Ahead of reworking the reference counting logic for platform devices,
encapsulate the assignment of the OF node for dynamically allocated
platform devices with the provided helper.

> diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c
> --- a/drivers/net/ethernet/marvell/mv643xx_eth.c
> +++ b/drivers/net/ethernet/marvell/mv643xx_eth.c
> @@ -2780,7 +2780,7 @@ static int mv643xx_eth_shared_of_add_port(struct platform_device *pdev,
>  		goto put_err;
>  	}
>  	ppdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
> -	ppdev->dev.of_node = of_node_get(pnp);
> +	platform_device_set_of_node(ppdev, pnp);

[Severity: High]
This is a pre-existing issue, but does the driver incorrectly assign a
devm_kzalloc() pointer to pdev->dev.platform_data elsewhere in this file?

In mv643xx_eth_shared_of_probe(), memory is allocated via devm_kzalloc() and
directly assigned to pdev->dev.platform_data. Because the parent pdev is
instantiated from the Device Tree, its standard lifecycle release function is
platform_device_release(), which unconditionally calls:

    kfree(pdev->dev.platform_data);

Calling kfree() on memory allocated by devm_kzalloc() is invalid since the
devres mechanism adds a hidden header, causing the pointer passed to kfree()
to be offset from the actual slab object, which can lead to a panic.

Furthermore, on driver unbind, devres frees the memory, leaving a dangling
pointer in pdev->dev.platform_data that could trigger a use-after-free or
double-free when the device is eventually released.

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Sashiko AI review · https://sashiko.dev/#/patchset/20260521-pdev-fwnode-ref-v1-0-88c324a1b8d2@oss.qualcomm.com?part=17