From mboxrd@z Thu Jan  1 00:00:00 1970
From: Claude Code Review Bot <claude-review@example.com>
To: dri-devel-reviews@example.com
Subject: Claude review: platform/surface: gpe: use platform_device_register_full()
Date: Sat, 16 May 2026 11:52:19 +1000
Message-ID: <review-patch2-20260513-swnode-remove-on-dev-unreg-v6-2-f9c58939df27@oss.qualcomm.com>
In-Reply-To: <20260513-swnode-remove-on-dev-unreg-v6-2-f9c58939df27@oss.qualcomm.com>
References: <20260513-swnode-remove-on-dev-unreg-v6-0-f9c58939df27@oss.qualcomm.com> <20260513-swnode-remove-on-dev-unreg-v6-2-f9c58939df27@oss.qualcomm.com>
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Patch Review

**Bug: `surface_gpe_exit()` is not updated and will use-after-free.**

The init conversion is clean -- replacing manual `fwnode_create_software_node()` + `platform_device_alloc()` + `platform_device_add()` with a single `platform_device_register_full()` using `.properties`:

```c
pdevinfo = (struct platform_device_info){
    .name = "surface_gpe",
    .id = PLATFORM_DEVID_NONE,
    .properties = match->driver_data,
};
pdev = platform_device_register_full(&pdevinfo);
```

However, the existing `surface_gpe_exit()` (unchanged by this patch) still does:

```c
static void __exit surface_gpe_exit(void)
{
    struct fwnode_handle *fwnode = surface_gpe_device->dev.fwnode;

    platform_device_unregister(surface_gpe_device);
    platform_driver_unregister(&surface_gpe_driver);
    fwnode_remove_software_node(fwnode);
}
```

With the old code, the fwnode was a standalone (non-managed) software node that persisted after `platform_device_unregister()`. With the new code, `platform_device_register_full()` with `.properties` calls `device_create_managed_software_node()`, which creates a **managed** node. During `platform_device_unregister()` -> `device_del()` -> `software_node_notify_remove()`, the managed node is cleaned up and its `kobject` refcount can reach zero, freeing the `swnode`. The subsequent `fwnode_remove_software_node(fwnode)` then dereferences freed memory.

**Fix needed**: The exit function should be updated to remove the `fwnode_remove_software_node()` call and the saved `fwnode` pointer:

```c
static void __exit surface_gpe_exit(void)
{
    platform_device_unregister(surface_gpe_device);
    platform_driver_unregister(&surface_gpe_driver);
}
```

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