[PATCH 0/4] Fix handling of GPIO keys and LEDs on geode

[PATCH 0/4] Fix handling of GPIO keys and LEDs on geode

[Dmitry Torokhov]

This series deal with breakage on geode caused by a recent conversion of
the board to use static device properties for configuring GPIO-connected
keys and LEDs. The issue was that PROPERTY_ENTRY_GPIO() would create a
temporary structure on stack for GPIO properties which would later be
discarded.

The first change patches the behavior using existing in kernel APIs so
that the bug can easily be fixed in stable kernels, and the other 3
improve the API and add safety checks.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
Dmitry Torokhov (4):
      x86/geode: fix on-stack property data usage
      software node: allow passing reference args to PROPERTY_ENTRY_REF
      software node: verify that property data is not on stack
      x86/geode: use PROPERTY_ENTRY_REF for GPIO properties

 arch/x86/platform/geode/geode-common.c | 24 ++++++++++++++++++------
 drivers/base/swnode.c                  |  9 +++++++++
 include/linux/property.h               |  9 ++++++++-
 3 files changed, 35 insertions(+), 7 deletions(-)
---
base-commit: b84a0ebe421ca56995ff78b66307667b62b3a900
change-id: 20260315-property-gpio-fix-51586cffcd5d

Thanks.

-- 
Dmitry

[PATCH 1/4] x86/geode: fix on-stack property data usage

[Dmitry Torokhov]

The PROPERTY_ENTRY_GPIO macro (and by extension PROPERTY_ENTRY_REF)
creates a temporary software_node_ref_args structure on the stack
when used in a runtime assignment. This results in the property
pointing to data that is invalid once the function returns.

Fix this by ensuring the GPIO reference data is not stored on stack and
using PROPERTY_ENTRY_REF_ARRAY_LEN() to point directly to the persistent
reference data.

Fixes: 298c9babadb8 ("x86/platform/geode: switch GPIO buttons and LEDs to software properties")
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 arch/x86/platform/geode/geode-common.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/arch/x86/platform/geode/geode-common.c b/arch/x86/platform/geode/geode-common.c
index 05189c5f7d2a..1843ae385e2d 100644
--- a/arch/x86/platform/geode/geode-common.c
+++ b/arch/x86/platform/geode/geode-common.c
@@ -28,8 +28,10 @@ static const struct software_node geode_gpio_keys_node = {
 	.properties = geode_gpio_keys_props,
 };
 
-static struct property_entry geode_restart_key_props[] = {
-	{ /* Placeholder for GPIO property */ },
+static struct software_node_ref_args geode_restart_gpio_ref;
+
+static const struct property_entry geode_restart_key_props[] = {
+	PROPERTY_ENTRY_REF_ARRAY_LEN("gpios", &geode_restart_gpio_ref, 1),
 	PROPERTY_ENTRY_U32("linux,code", KEY_RESTART),
 	PROPERTY_ENTRY_STRING("label", "Reset button"),
 	PROPERTY_ENTRY_U32("debounce-interval", 100),
@@ -64,8 +66,7 @@ int __init geode_create_restart_key(unsigned int pin)
 	struct platform_device *pd;
 	int err;
 
-	geode_restart_key_props[0] = PROPERTY_ENTRY_GPIO("gpios",
-							 &geode_gpiochip_node,
+	geode_restart_gpio_ref = SOFTWARE_NODE_REFERENCE(&geode_gpiochip_node,
 							 pin, GPIO_ACTIVE_LOW);
 
 	err = software_node_register_node_group(geode_gpio_keys_swnodes);
@@ -99,6 +100,7 @@ int __init geode_create_leds(const char *label, const struct geode_led *leds,
 	const struct software_node *group[MAX_LEDS + 2] = { 0 };
 	struct software_node *swnodes;
 	struct property_entry *props;
+	struct software_node_ref_args *gpio_refs;
 	struct platform_device_info led_info = {
 		.name	= "leds-gpio",
 		.id	= PLATFORM_DEVID_NONE,
@@ -127,6 +129,12 @@ int __init geode_create_leds(const char *label, const struct geode_led *leds,
 		goto err_free_swnodes;
 	}
 
+	gpio_refs = kzalloc_objs(*gpio_refs, n_leds);
+	if (!gpio_refs) {
+		err = -ENOMEM;
+		goto err_free_props;
+	}
+
 	group[0] = &geode_gpio_leds_node;
 	for (i = 0; i < n_leds; i++) {
 		node_name = kasprintf(GFP_KERNEL, "%s:%d", label, i);
@@ -135,9 +143,11 @@ int __init geode_create_leds(const char *label, const struct geode_led *leds,
 			goto err_free_names;
 		}
 
+		gpio_refs[i] = SOFTWARE_NODE_REFERENCE(&geode_gpiochip_node,
+						       leds[i].pin,
+						       GPIO_ACTIVE_LOW);
 		props[i * 3 + 0] =
-			PROPERTY_ENTRY_GPIO("gpios", &geode_gpiochip_node,
-					    leds[i].pin, GPIO_ACTIVE_LOW);
+			PROPERTY_ENTRY_REF_ARRAY_LEN("gpios", &gpio_refs[i], 1);
 		props[i * 3 + 1] =
 			PROPERTY_ENTRY_STRING("linux,default-trigger",
 					      leds[i].default_on ?
@@ -171,6 +181,8 @@ int __init geode_create_leds(const char *label, const struct geode_led *leds,
 err_free_names:
 	while (--i >= 0)
 		kfree(swnodes[i].name);
+	kfree(gpio_refs);
+err_free_props:
 	kfree(props);
 err_free_swnodes:
 	kfree(swnodes);

-- 
2.53.0.1018.g2bb0e51243-goog