[PATCH] hwmon: Ensure that 'dev' passed to hwmon_notify_event() is a hwmon device

[Guenter Roeck <linux@roeck-us.net>]

The device parameter of hwmon_notify_event() must be a hardware monitoring
device. Since this is easy to get wrong, and since passing a non-hwmon
device may result in a crash, generate a warning traceback and abort if
a wrong device class is passed as parameter.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/hwmon/hwmon.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index 3e65fc6d25eb..24ce28239316 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -336,11 +336,16 @@ static int hwmon_attr_base(enum hwmon_sensor_types type)
  * attached to an i2c client device.
  */
 
-static int hwmon_match_device(struct device *dev, const void *data)
+static bool is_hwmon_device(struct device *dev)
 {
 	return dev->class == &hwmon_class;
 }
 
+static int hwmon_match_device(struct device *dev, const void *data)
+{
+	return is_hwmon_device(dev);
+}
+
 static ssize_t pec_show(struct device *dev, const struct device_attribute *dummy,
 			char *buf)
 {
@@ -781,6 +786,9 @@ int hwmon_notify_event(struct device *dev, enum hwmon_sensor_types type,
 	const char *template;
 	int base;
 
+	if (WARN(!is_hwmon_device(dev), "%s is not a hardware monitoring device\n",
+		 dev_name(dev)))
+		return -EINVAL;
 	if (type >= ARRAY_SIZE(__templates))
 		return -EINVAL;
 	if (attr >= __templates_size[type])
-- 
2.45.2