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authorAxel Lin <axel.lin@ingics.com>2014-07-31 03:43:19 +0200
committerGuenter Roeck <linux@roeck-us.net>2014-07-31 06:42:37 +0200
commitcf44819c98db11163f58f08b822d626c7a8f5188 (patch)
tree68af0f6580a73753e5c43bc51ba46a87aaa1a18b /drivers/hwmon/amc6821.c
parenthwmon: (lm78) Fix overflow problems seen when writing large temperature limits (diff)
downloadlinux-cf44819c98db11163f58f08b822d626c7a8f5188.tar.xz
linux-cf44819c98db11163f58f08b822d626c7a8f5188.zip
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>
Diffstat (limited to 'drivers/hwmon/amc6821.c')
-rw-r--r--drivers/hwmon/amc6821.c17
1 files changed, 11 insertions, 6 deletions
diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 9f2be3dd28f3..8a67ec6279a4 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -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;