[PATCH v2 1/4] hwmon: (ina2xx) Acquire hwmon_lock in shunt_resistor_show()

shunt_resistor_store() currently acquires hwmon_lock to set
data->rshunt, but the corresponding access in shunt_resistor_show() is
unprotected. Acquire the lock in shunt_resistor_show() as well to ensure
proper synchronization.

Fixes: 3ad867001c91 ("hwmon: (ina2xx) fix sysfs shunt resistor read access")
Reported-by: Sashiko <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Jared Kangas <[email protected]>
---
 drivers/hwmon/ina2xx.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
index c4742e84b999d..f6c63ce1ef193 100644
--- a/drivers/hwmon/ina2xx.c
+++ b/drivers/hwmon/ina2xx.c
@@ -859,8 +859,12 @@ static ssize_t shunt_resistor_show(struct device *dev,
 				   struct device_attribute *da, char *buf)
 {
 	struct ina2xx_data *data = dev_get_drvdata(dev);
+	long rshunt;
 
-	return sysfs_emit(buf, "%li\n", data->rshunt);
+	scoped_guard(hwmon_lock, dev) {
+		rshunt = data->rshunt;
+	}
+	return sysfs_emit(buf, "%li\n", rshunt);
 }
 
 static ssize_t shunt_resistor_store(struct device *dev,

-- 
2.55.0