Commit 38463721 authored May 29, 2019 by Adamski, Krzysztof (Nokia - PL/Wroclaw) Committed by Guenter Roeck Jun 05, 2019

hwmon: (pmbus/core) mutex_lock write in pmbus_set_samples



update_lock is a mutex intended to protect write operations. It was not
taken, however, when _pmbus_write_word_data is called from
pmbus_set_samples() function which may cause problems especially when
some PMBUS_VIRT_* operation is implemented as a read-modify-write cycle.

This patch makes sure the lock is held during the operation.

Fixes: 49c4455d ("hwmon: (pmbus) Introduce PMBUS_VIRT_*_SAMPLES registers")
Signed-off-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
[groeck: Declared and initialized missing 'data' variable]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

parent c41dd48e

drivers/hwmon/pmbus/pmbus_core.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -1942,11 +1942,14 @@ static ssize_t pmbus_set_samples(struct device *dev,
		long val;
		struct i2c_client *client = to_i2c_client(dev->parent);
		struct pmbus_samples_reg *reg = to_samples_reg(devattr);
		struct pmbus_data *data = i2c_get_clientdata(client);

		if (kstrtol(buf, 0, &val) < 0)
		return -EINVAL;

		mutex_lock(&data->update_lock);
		ret = _pmbus_write_word_data(client, reg->page, reg->attr->reg, val);
		mutex_unlock(&data->update_lock);

		return ret ? : count;
		}