linux-kernel - [PATCH v3 1/3] drivers: base: Don't match devices with NULL of

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Message-ID: <20241216201148.535115-2-briannorris@chromium.org>
Date: Mon, 16 Dec 2024 12:11:42 -0800
From: Brian Norris <briannorris@...omium.org>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Maxime Ripard <mripard@...nel.org>,
	linux-acpi@...r.kernel.org,
	Rae Moar <rmoar@...gle.com>,
	Rob Herring <robh@...nel.org>,
	David Gow <davidgow@...gle.com>,
	linux-kselftest@...r.kernel.org,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	kunit-dev@...glegroups.com,
	linux-kernel@...r.kernel.org,
	Brian Norris <briannorris@...omium.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: [PATCH v3 1/3] drivers: base: Don't match devices with NULL of_node/fwnode/etc

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) <robh@...nel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Brian Norris <briannorris@...omium.org>
---

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(-)

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);
 
-- 
2.47.1.613.gc27f4b7a9f-goog