* [lm-sensors] [RFT][PATCH] hwmon: (amc6821) Fix possible race condition bug
@ 2014-07-31 1:43 Axel Lin
2014-07-31 4:43 ` Guenter Roeck
0 siblings, 1 reply; 2+ messages in thread
From: Axel Lin @ 2014-07-31 1:43 UTC (permalink / raw)
To: lm-sensors
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>
---
drivers/hwmon/amc6821.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 66b994a..12e851a 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -415,11 +415,13 @@ 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) {
@@ -436,14 +438,15 @@ 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;
}
@@ -542,8 +545,9 @@ 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,
@@ -699,13 +703,14 @@ 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;
--
1.9.1
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [lm-sensors] [RFT][PATCH] hwmon: (amc6821) Fix possible race condition bug
2014-07-31 1:43 [lm-sensors] [RFT][PATCH] hwmon: (amc6821) Fix possible race condition bug Axel Lin
@ 2014-07-31 4:43 ` Guenter Roeck
0 siblings, 0 replies; 2+ messages in thread
From: Guenter Roeck @ 2014-07-31 4:43 UTC (permalink / raw)
To: lm-sensors
On 07/30/2014 06:43 PM, Axel Lin wrote:
> 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>
Good catch.
Applied.
Thanks,
Guenter
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lm-sensors mailing list
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http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
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