Eric,
On Thu, Jun 10, 2021 at 05:55:40PM +0100, Colin Ian King wrote:
> Hi,
>
> Static analysis with Coverity on linux-next has detected a potential
> issue in drivers/hwmon/pmbus/pmbus_core.c with the following commit:
>
No need to send a patch - I fixed it up by pre-initializing ret.
Thanks,
Guenter
> commit 999d577d7c007d38ab83eee4532d107c2233f78f
> Author: Erik Rosen <erik.rosen@xxxxxxxxxxxxx>
> Date: Wed Jun 9 11:32:06 2021 +0200
>
> hwmon: (pmbus) Add support for reading direct mode coefficients
>
> The analysis is as follows:
>
> 2219 static int pmbus_init_coefficients(struct i2c_client *client,
> 2220 struct pmbus_driver_info *info)
> 2221 {
>
> 1. var_decl: Declaring variable ret without initializer.
>
> 2222 int i, n, ret;
> 2223 const struct pmbus_class_attr_map *map;
> 2224 const struct pmbus_sensor_attr *attr;
> 2225
>
> 2. Condition i < 6UL /* sizeof (class_attr_map) / sizeof
> (class_attr_map[0]) + (int)sizeof (struct
> pmbus_init_coefficients::[unnamed type]) */, taking true branch.
>
> 5. Condition i < 6UL /* sizeof (class_attr_map) / sizeof
> (class_attr_map[0]) + (int)sizeof (struct
> pmbus_init_coefficients::[unnamed type]) */, taking true branch.
>
> 8. Condition i < 6UL /* sizeof (class_attr_map) / sizeof
> (class_attr_map[0]) + (int)sizeof (struct
> pmbus_init_coefficients::[unnamed type]) */, taking true branch.
>
> 2226 for (i = 0; i < ARRAY_SIZE(class_attr_map); i++) {
> 2227 map = &class_attr_map[i];
>
> 3. Condition info->format[map->class] != direct, taking true branch.
> 6. Condition info->format[map->class] != direct, taking true branch.
> 9. Condition info->format[map->class] != direct, taking false branch.
>
> 2228 if (info->format[map->class] != direct)
>
> 4. Continuing loop.
> 7. Continuing loop.
>
> 2229 continue;
>
> 10. Condition n < map->nattr, taking true branch.
> 13. Condition n < map->nattr, taking true branch.
> 16. Condition n < map->nattr, taking false branch.
>
> 2230 for (n = 0; n < map->nattr; n++) {
> 2231 attr = &map->attr[n];
>
> 11. Condition map->class != attr->class, taking true branch.
> 14. Condition map->class != attr->class, taking true branch.
> 2232 if (map->class != attr->class)
> 12. Continuing loop.
> 15. Continuing loop.
>
> 2233 continue;
> 2234 ret = pmbus_read_coefficients(client, info,
> attr);
> 2235 if (ret >= 0)
> 2236 break;
> 2237 }
>
> Uninitialized scalar variable (UNINIT)
> 17. uninit_use: Using uninitialized value ret.
>
> 2238 if (ret < 0) {
> 2239 dev_err(&client->dev,
> 2240 "No coefficients found for sensor
> class %d\n",
> 2241 map->class);
> 2242 return -EINVAL;
> 2243 }
> 2244 }
> 2245
> 2246 return 0;
> 2247 }
>
> With the continue statements on line 2233 (or if map->nattr is zero) it
> may be possible that ret is never assigned a value and so the check on
> line 2238 could be checking an uninitialized variable ret. I'm not sure
> if this is a false positive, but it may be worth initializing ret to
> some sane value to catch these corner cases.
>
> Colin
>
