[v3,1/3] drivers: base: Don't match devices with NULL of_node/fwnode/etc

Commit Message

Brian Norris Dec. 16, 2024, 8:11 p.m. UTC

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).

Reviewed-by: Rob Herring (Arm) <[e-mail]>
Acked-by: Rafael J. Wysocki <[e-mail]>
Signed-off-by: Brian Norris <[e-mail]>
---

Changes in v3:
 * Add Rafael's Acked-by

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

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

Patch

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);