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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: Axel Lin <axel.lin@ingics.com>
Cc: stable@vger.kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Axel Lin 2014-07-31 09:43:19 +08:00 committed by Guenter Roeck
parent 1074d683a5
commit cf44819c98
1 changed files with 11 additions and 6 deletions
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17
drivers/hwmon/amc6821.c
View File

@ -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;