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

Peng Fan (OSS)
2023-08-18T01:55:58Z

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.

Fixes: 0f8e5651095b ("of/platform: Propagate firmware node by calling device_set_node()")
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---

V2:
- Per Andy's comment, use of_fwnode_handle(of_node_get(np))
- release amba device of_node refcount when releasing amba device, this is
done from code inspection, no test.

drivers/amba/bus.c | 1 +
drivers/of/platform.c | 4 ++--
2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index ce88af9eb562..09e72967b8ab 100644
--- 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);
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
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)
--
2.37.1