Re: [PATCH V2] of/platform: increase refcount of fwnode

Andy Shevchenko
2023-08-18T10:52:53Z

On Fri, Aug 18, 2023 at 09:59:32AM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
>
> commit 0f8e5651095b
> ("of/platform: Propagate firmware node by calling device_set_node()")
> use of_fwnode_handle to replace of_node_get, which introduces a side
> effect that the refcount is not increased. Then the out of tree
> jailhouse hypervisor enable/disable test will trigger kernel dump in
> of_overlay_remove, with the following sequence
> "
> of_changeset_revert(&overlay_changeset);
> of_changeset_destroy(&overlay_changeset);
> of_overlay_remove(&overlay_id);
> "
>
> So increase the refcount to avoid issues.

...

> This patch also release the refcount when releasing amba device to avoid
> refcount leakage.

> --- a/drivers/amba/bus.c
> +++ b/drivers/amba/bus.c
> @@ -528,6 +528,7 @@ static void amba_device_release(struct device *dev)
> {
> struct amba_device *d = to_amba_device(dev);
>
> + of_node_put(d->dev.of_node);
> if (d->res.parent)
> release_resource(&d->res);
> mutex_destroy(&d->periphid_lock);

As I said, this change should be in a separate patch with the correct Fixes tag.

> index 267d8c9a5612..d328bbb679c7 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -175,7 +175,7 @@ struct platform_device *of_device_alloc(struct device_node *np,
> }
>
> /* setup generic device info */
> - device_set_node(&dev->dev, of_fwnode_handle(np));
> + device_set_node(&dev->dev, of_fwnode_handle(of_node_get(np)));
> dev->dev.parent = parent ? : &platform_bus;
>
> if (bus_id)
> @@ -273,7 +273,7 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
> dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
>
> /* setup generic device info */
> - device_set_node(&dev->dev, of_fwnode_handle(node));
> + device_set_node(&dev->dev, of_fwnode_handle(of_node_get(node)));
> dev->dev.parent = parent ? : &platform_bus;
> dev->dev.platform_data = platform_data;
> if (bus_id)

Without AMBA changes,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
thank you for fixing this!

--
With Best Regards,
Andy Shevchenko