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Commit cf44819c authored by Axel Lin's avatar Axel Lin Committed by Guenter Roeck
Browse files

hwmon: (amc6821) Fix possible race condition bug 



Ensure mutex lock protects the read-modify-write period to prevent possible
race condition bug.
In additional, update data->valid should also be protected by the mutex lock.

Signed-off-by: default avatarAxel Lin <axel.lin@ingics.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 1074d683

drivers/hwmon/amc6821.c

+11 −6
Original line number Diff line number Diff line
@@ -360,11 +360,13 @@ static ssize_t set_pwm1_enable( 
	if (config)

		return config;



	mutex_lock(&data->update_lock);

	config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF1);

	if (config < 0) {

			dev_err(&client->dev,

			"Error reading configuration register, aborting.\n");

			return config;

			count = config;

			goto unlock;

	}



	switch (val) {
@@ -381,14 +383,15 @@ static ssize_t set_pwm1_enable( 
		config |= AMC6821_CONF1_FDRC1;

		break;

	default:

		return -EINVAL;

		count = -EINVAL;

		goto unlock;

	}

	mutex_lock(&data->update_lock);

	if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF1, config)) {

			dev_err(&client->dev,

			"Configuration register write error, aborting.\n");

			count = -EIO;

	}

unlock:

	mutex_unlock(&data->update_lock);

	return count;

}
@@ -493,8 +496,9 @@ static ssize_t set_temp_auto_point_temp( 
		return -EINVAL;

	}



	data->valid = 0;

	mutex_lock(&data->update_lock);

	data->valid = 0;



	switch (ix) {

	case 0:

		ptemp[0] = clamp_val(val / 1000, 0,
@@ -658,13 +662,14 @@ static ssize_t set_fan1_div( 
	if (config)

		return config;



	mutex_lock(&data->update_lock);

	config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF4);

	if (config < 0) {

		dev_err(&client->dev,

			"Error reading configuration register, aborting.\n");

		return config;

		count = config;

		goto EXIT;

	}

	mutex_lock(&data->update_lock);

	switch (val) {

	case 2:

		config &= ~AMC6821_CONF4_PSPR;