Re: [PATCH] hwmon: lm80: fix a missing check of return value
From: Dan Carpenter
Date: Wed Jan 02 2019 - 10:24:55 EST
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