[bug report] hwmon: (it87) Test for error in it87_update_device

[bug report] hwmon: (it87) Test for error in it87_update_device

[Dan Carpenter]

Hello Frank Crawford,

The patch 27302e7a46f5: "hwmon: (it87) Test for error in
it87_update_device" from Apr 16, 2023, leads to the following Smatch
static checker warning:

	drivers/hwmon/it87.c:1147 show_temp_type()
	error: 'data' dereferencing possible ERR_PTR()

drivers/hwmon/it87.c
    1141 static ssize_t show_temp_type(struct device *dev, struct device_attribute *attr,
    1142                               char *buf)
    1143 {
    1144         struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
    1145         int nr = sensor_attr->index;
    1146         struct it87_data *data = it87_update_device(dev);
--> 1147         u8 reg = data->sensor;            /* In case value is updated while used */
                          ^^^^^^^^^^^^
    1148         u8 extra = data->extra;
                            ^^^^^^^^^^^

    1149 
    1150         if (IS_ERR(data))

This new check happens too late.

    1151                 return PTR_ERR(data);
    1152 

regards,
dan carpenter

Re: [bug report] hwmon: (it87) Test for error in it87_update_device

[Guenter Roeck]

On 4/21/23 03:45, Dan Carpenter wrote:
> Hello Frank Crawford,
> 
> The patch 27302e7a46f5: "hwmon: (it87) Test for error in
> it87_update_device" from Apr 16, 2023, leads to the following Smatch
> static checker warning:
> 
> 	drivers/hwmon/it87.c:1147 show_temp_type()
> 	error: 'data' dereferencing possible ERR_PTR()
> 

I updated the original patch. No need to send a fix or new version.

Thanks,
Guenter

> drivers/hwmon/it87.c
>      1141 static ssize_t show_temp_type(struct device *dev, struct device_attribute *attr,
>      1142                               char *buf)
>      1143 {
>      1144         struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
>      1145         int nr = sensor_attr->index;
>      1146         struct it87_data *data = it87_update_device(dev);
> --> 1147         u8 reg = data->sensor;            /* In case value is updated while used */
>                            ^^^^^^^^^^^^
>      1148         u8 extra = data->extra;
>                              ^^^^^^^^^^^
> 
>      1149
>      1150         if (IS_ERR(data))
> 
> This new check happens too late.
> 
>      1151                 return PTR_ERR(data);
>      1152
> 
> regards,
> dan carpenter

Re: [bug report] hwmon: (it87) Test for error in it87_update_device

[Frank Crawford]

On Fri, 2023-04-21 at 07:28 -0700, Guenter Roeck wrote:
> On 4/21/23 03:45, Dan Carpenter wrote:
> > Hello Frank Crawford,
> > 
> > The patch 27302e7a46f5: "hwmon: (it87) Test for error in
> > it87_update_device" from Apr 16, 2023, leads to the following
> > Smatch
> > static checker warning:
> > 
> >         drivers/hwmon/it87.c:1147 show_temp_type()
> >         error: 'data' dereferencing possible ERR_PTR()
> > 
> 
> I updated the original patch. No need to send a fix or new version.

Thanks for that Guenter.

> 
> Thanks,
> Guenter

Regards
Frank
> 
> > drivers/hwmon/it87.c
> >      1141 static ssize_t show_temp_type(struct device *dev, struct
> > device_attribute *attr,
> >      1142                               char *buf)
> >      1143 {
> >      1144         struct sensor_device_attribute *sensor_attr =
> > to_sensor_dev_attr(attr);
> >      1145         int nr = sensor_attr->index;
> >      1146         struct it87_data *data = it87_update_device(dev);
> > --> 1147         u8 reg = data->sensor;            /* In case value
> > is updated while used */
> >                            ^^^^^^^^^^^^
> >      1148         u8 extra = data->extra;
> >                              ^^^^^^^^^^^
> > 
> >      1149
> >      1150         if (IS_ERR(data))
> > 
> > This new check happens too late.
> > 
> >      1151                 return PTR_ERR(data);
> >      1152
> > 
> > regards,
> > dan carpenter
>