Commit 3e6d3af6 authored by Axel Lin's avatar Axel Lin Committed by Ben Hutchings

hwmon: (amc6821) Fix possible race condition bug

commit cf44819c upstream.

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>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 0719a7b8
......@@ -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;
}
......@@ -495,8 +498,9 @@ 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] = SENSORS_LIMIT(val / 1000, 0,
......@@ -669,13 +673,14 @@ 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;
......
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