[PATCH v2 1/3] drivers: base: Don't match devices with NULL of_node/fwnode/etc

Brian Norris
2024-12-12T00:32:10Z

of_find_device_by_node(), bus_find_device_by_of_node(),
bus_find_device_by_fwnode(), ..., all produce arbitrary results when
provided with a NULL of_node, fwnode, ACPI handle, etc. This is
counterintuitive, and the source of a few bugs, such as the one fixed by
commit 5c8418cf4025 ("PCI/pwrctrl: Unregister platform device only if
one actually exists").

It's hard to imagine a good reason that these device_match_*() APIs
should return 'true' for a NULL argument. Augment these to return 0
(false).

Signed-off-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
---

Changes in v2:
* Add Rob's Reviewed-by

drivers/base/core.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 94865c9d8adc..2b7b13fc36d7 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -5246,13 +5246,13 @@ EXPORT_SYMBOL_GPL(device_match_name);

int device_match_of_node(struct device *dev, const void *np)
{
- return dev->of_node == np;
+ return np && dev->of_node == np;
}
EXPORT_SYMBOL_GPL(device_match_of_node);

int device_match_fwnode(struct device *dev, const void *fwnode)
{
- return dev_fwnode(dev) == fwnode;
+ return fwnode && dev_fwnode(dev) == fwnode;
}
EXPORT_SYMBOL_GPL(device_match_fwnode);

@@ -5264,13 +5264,13 @@ EXPORT_SYMBOL_GPL(device_match_devt);

int device_match_acpi_dev(struct device *dev, const void *adev)
{
- return ACPI_COMPANION(dev) == adev;
+ return adev && ACPI_COMPANION(dev) == adev;
}
EXPORT_SYMBOL(device_match_acpi_dev);

int device_match_acpi_handle(struct device *dev, const void *handle)
{
- return ACPI_HANDLE(dev) == handle;
+ return handle && ACPI_HANDLE(dev) == handle;
}
EXPORT_SYMBOL(device_match_acpi_handle);

--
2.47.0.338.g60cca15819-goog