Message ID | 20181221061304.59684-1-kjlu@umn.edu (mailing list archive) |
---|---|
State | Superseded |
Headers | show |
Series | hwmon: lm80: fix a missing check of return value | expand |
On 12/20/18 10:13 PM, Kangjie Lu wrote: > If lm80_read_value() fails, it returns a negative number instead of the > correct read data. Therefore, we should avoid using the data if it > fails. > > The fix checks if lm80_read_value() fails, and if so, returns with the > error number. > > Signed-off-by: Kangjie Lu <kjlu@umn.edu> > --- > drivers/hwmon/lm80.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/drivers/hwmon/lm80.c b/drivers/hwmon/lm80.c > index 08e3945a6fbf..fca6363cd77f 100644 > --- a/drivers/hwmon/lm80.c > +++ b/drivers/hwmon/lm80.c > @@ -360,9 +360,11 @@ static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr, > struct i2c_client *client = data->client; > unsigned long min, val; > u8 reg; > - int err = kstrtoul(buf, 10, &val); > - if (err < 0) > - return err; > + int ret; > + In the other patch you are using 'rv'. Please use consistent variable names. Also, please use "hwmon: (lm80) <description>" as subject, and use different subjects for both patches so we can distinguish them without looking into each patch itself. This applies to the other patch as well. Thanks, Guenter > + ret = kstrtoul(buf, 10, &val); > + if (ret < 0) > + return ret; > > /* Save fan_min */ > mutex_lock(&data->update_lock); > @@ -390,8 +392,11 @@ static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr, > return -EINVAL; > } > > - reg = (lm80_read_value(client, LM80_REG_FANDIV) & > - ~(3 << (2 * (nr + 1)))) | (data->fan_div[nr] << (2 * (nr + 1))); > + ret = lm80_read_value(client, LM80_REG_FANDIV); > + if (ret < 0) > + return ret; > + reg = (ret & ~(3 << (2 * (nr + 1)))) > + | (data->fan_div[nr] << (2 * (nr + 1))); > lm80_write_value(client, LM80_REG_FANDIV, reg); > > /* Restore fan_min */ >
Hi Kangjie, Thank you for the patch! Perhaps something to improve: url: https://github.com/0day-ci/linux/commits/Kangjie-Lu/hwmon-lm80-fix-a-missing-check-of-return-value/20181222-023000 base: https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next smatch warnings: drivers/hwmon/lm80.c:408 set_fan_div() warn: inconsistent returns 'mutex:&data->update_lock'. Locked on: line 397 Unlocked on: line 367 # https://github.com/0day-ci/linux/commit/7612ba0bef1defb6de3290accca07633ccfd3365 git remote add linux-review https://github.com/0day-ci/linux git remote update linux-review git checkout 7612ba0bef1defb6de3290accca07633ccfd3365 vim +408 drivers/hwmon/lm80.c ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 348 1160631b1 drivers/hwmon/lm80.c Guenter Roeck 2012-01-19 349 /* 1160631b1 drivers/hwmon/lm80.c Guenter Roeck 2012-01-19 350 * Note: we save and restore the fan minimum here, because its value is 1160631b1 drivers/hwmon/lm80.c Guenter Roeck 2012-01-19 351 * determined in part by the fan divisor. This follows the principle of 1160631b1 drivers/hwmon/lm80.c Guenter Roeck 2012-01-19 352 * least surprise; the user doesn't expect the fan minimum to change just 1160631b1 drivers/hwmon/lm80.c Guenter Roeck 2012-01-19 353 * because the divisor changed. 1160631b1 drivers/hwmon/lm80.c Guenter Roeck 2012-01-19 354 */ f8181762a drivers/hwmon/lm80.c Jean Delvare 2008-01-05 355 static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr, f8181762a drivers/hwmon/lm80.c Jean Delvare 2008-01-05 356 const char *buf, size_t count) ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 357 { f8181762a drivers/hwmon/lm80.c Jean Delvare 2008-01-05 358 int nr = to_sensor_dev_attr(attr)->index; 118c9a61f drivers/hwmon/lm80.c Guenter Roeck 2014-04-04 359 struct lm80_data *data = dev_get_drvdata(dev); 118c9a61f drivers/hwmon/lm80.c Guenter Roeck 2014-04-04 360 struct i2c_client *client = data->client; 6a9e7c4c0 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-10 361 unsigned long min, val; ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 362 u8 reg; 7612ba0be drivers/hwmon/lm80.c Kangjie Lu 2018-12-21 363 int ret; 7612ba0be drivers/hwmon/lm80.c Kangjie Lu 2018-12-21 364 7612ba0be drivers/hwmon/lm80.c Kangjie Lu 2018-12-21 365 ret = kstrtoul(buf, 10, &val); 7612ba0be drivers/hwmon/lm80.c Kangjie Lu 2018-12-21 366 if (ret < 0) 7612ba0be drivers/hwmon/lm80.c Kangjie Lu 2018-12-21 367 return ret; ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 368 ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 369 /* Save fan_min */ 9a61bf630 drivers/hwmon/lm80.c Ingo Molnar 2006-01-18 370 mutex_lock(&data->update_lock); 85b3ee07b drivers/hwmon/lm80.c Guenter Roeck 2014-04-13 371 min = FAN_FROM_REG(data->fan[f_min][nr], ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 372 DIV_FROM_REG(data->fan_div[nr])); ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 373 ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 374 switch (val) { 66b3b1f75 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-04 375 case 1: 66b3b1f75 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-04 376 data->fan_div[nr] = 0; 66b3b1f75 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-04 377 break; 66b3b1f75 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-04 378 case 2: 66b3b1f75 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-04 379 data->fan_div[nr] = 1; 66b3b1f75 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-04 380 break; 66b3b1f75 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-04 381 case 4: 66b3b1f75 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-04 382 data->fan_div[nr] = 2; 66b3b1f75 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-04 383 break; 66b3b1f75 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-04 384 case 8: 66b3b1f75 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-04 385 data->fan_div[nr] = 3; 66b3b1f75 drivers/hwmon/lm80.c Frans Meulenbroeks 2012-01-04 386 break; ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 387 default: 118c9a61f drivers/hwmon/lm80.c Guenter Roeck 2014-04-04 388 dev_err(dev, b55f37572 drivers/hwmon/lm80.c Guenter Roeck 2013-01-10 389 "fan_div value %ld not supported. Choose one of 1, 2, 4 or 8!\n", b55f37572 drivers/hwmon/lm80.c Guenter Roeck 2013-01-10 390 val); 9a61bf630 drivers/hwmon/lm80.c Ingo Molnar 2006-01-18 391 mutex_unlock(&data->update_lock); ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 392 return -EINVAL; ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 393 } ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 394 7612ba0be drivers/hwmon/lm80.c Kangjie Lu 2018-12-21 395 ret = lm80_read_value(client, LM80_REG_FANDIV); 7612ba0be drivers/hwmon/lm80.c Kangjie Lu 2018-12-21 396 if (ret < 0) 7612ba0be drivers/hwmon/lm80.c Kangjie Lu 2018-12-21 397 return ret; ^^^^^^^^^^ Need to drop the lock before returning. 7612ba0be drivers/hwmon/lm80.c Kangjie Lu 2018-12-21 398 reg = (ret & ~(3 << (2 * (nr + 1)))) 7612ba0be drivers/hwmon/lm80.c Kangjie Lu 2018-12-21 399 | (data->fan_div[nr] << (2 * (nr + 1))); ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 400 lm80_write_value(client, LM80_REG_FANDIV, reg); ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 401 ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 402 /* Restore fan_min */ 85b3ee07b drivers/hwmon/lm80.c Guenter Roeck 2014-04-13 403 data->fan[f_min][nr] = FAN_TO_REG(min, DIV_FROM_REG(data->fan_div[nr])); 85b3ee07b drivers/hwmon/lm80.c Guenter Roeck 2014-04-13 404 lm80_write_value(client, LM80_REG_FAN_MIN(nr + 1), 85b3ee07b drivers/hwmon/lm80.c Guenter Roeck 2014-04-13 405 data->fan[f_min][nr]); 9a61bf630 drivers/hwmon/lm80.c Ingo Molnar 2006-01-18 406 mutex_unlock(&data->update_lock); ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 407 ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 @408 return count; ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 409 } ^1da177e4 drivers/i2c/chips/lm80.c Linus Torvalds 2005-04-16 410 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
On Wed, Jan 02, 2019 at 06:23:59PM +0300, Dan Carpenter wrote: > Hi Kangjie, > > Thank you for the patch! Perhaps something to improve: > > url: https://github.com/0day-ci/linux/commits/Kangjie-Lu/hwmon-lm80-fix-a-missing-check-of-return-value/20181222-023000 > base: https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next > Fix already queued, waiting for end of commit window. Thanks, Guenter
diff --git a/drivers/hwmon/lm80.c b/drivers/hwmon/lm80.c index 08e3945a6fbf..fca6363cd77f 100644 --- a/drivers/hwmon/lm80.c +++ b/drivers/hwmon/lm80.c @@ -360,9 +360,11 @@ static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr, struct i2c_client *client = data->client; unsigned long min, val; u8 reg; - int err = kstrtoul(buf, 10, &val); - if (err < 0) - return err; + int ret; + + ret = kstrtoul(buf, 10, &val); + if (ret < 0) + return ret; /* Save fan_min */ mutex_lock(&data->update_lock); @@ -390,8 +392,11 @@ static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr, return -EINVAL; } - reg = (lm80_read_value(client, LM80_REG_FANDIV) & - ~(3 << (2 * (nr + 1)))) | (data->fan_div[nr] << (2 * (nr + 1))); + ret = lm80_read_value(client, LM80_REG_FANDIV); + if (ret < 0) + return ret; + reg = (ret & ~(3 << (2 * (nr + 1)))) + | (data->fan_div[nr] << (2 * (nr + 1))); lm80_write_value(client, LM80_REG_FANDIV, reg); /* Restore fan_min */
If lm80_read_value() fails, it returns a negative number instead of the correct read data. Therefore, we should avoid using the data if it fails. The fix checks if lm80_read_value() fails, and if so, returns with the error number. Signed-off-by: Kangjie Lu <kjlu@umn.edu> --- drivers/hwmon/lm80.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)