| Message ID | 1466822827-31231-1-git-send-email-linux@roeck-us.net (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On 06/24/2016 09:47 PM, Guenter Roeck wrote: > The result of an integer divide by an unsigned is undefined. > This causes unexpected results when writing negative values > into the limit registers. > > Maintain the shunt_resistors variables as signed integer to avoid > the problem. Also, for simplicity and ease of use, clamp shunt > resistor value on writes instead of rejecting bad values. > > Cc: Andrew F. Davis <afd@ti.com> > Signed-off-by: Guenter Roeck <linux@roeck-us.net> > --- Acked-by: Andrew F. Davis <afd@ti.com> > drivers/hwmon/ina3221.c | 13 ++++++------- > 1 file changed, 6 insertions(+), 7 deletions(-) > > diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c > index d055b6a2266b..e6b49500c52a 100644 > --- a/drivers/hwmon/ina3221.c > +++ b/drivers/hwmon/ina3221.c > @@ -95,7 +95,7 @@ static const unsigned int register_channel[] = { > struct ina3221_data { > struct regmap *regmap; > struct regmap_field *fields[F_MAX_FIELDS]; > - unsigned int shunt_resistors[INA3221_NUM_CHANNELS]; > + int shunt_resistors[INA3221_NUM_CHANNELS]; > }; > > static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg, > @@ -155,7 +155,7 @@ static ssize_t ina3221_show_current(struct device *dev, > struct ina3221_data *ina = dev_get_drvdata(dev); > unsigned int reg = sd_attr->index; > unsigned int channel = register_channel[reg]; > - unsigned int resistance_uo = ina->shunt_resistors[channel]; > + int resistance_uo = ina->shunt_resistors[channel]; > int val, current_ma, voltage_nv, ret; > > ret = ina3221_read_value(ina, reg, &val); > @@ -176,7 +176,7 @@ static ssize_t ina3221_set_current(struct device *dev, > struct ina3221_data *ina = dev_get_drvdata(dev); > unsigned int reg = sd_attr->index; > unsigned int channel = register_channel[reg]; > - unsigned int resistance_uo = ina->shunt_resistors[channel]; > + int resistance_uo = ina->shunt_resistors[channel]; > int val, current_ma, voltage_uv, ret; > > ret = kstrtoint(buf, 0, ¤t_ma); > @@ -223,15 +223,14 @@ static ssize_t ina3221_set_shunt(struct device *dev, > struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr); > struct ina3221_data *ina = dev_get_drvdata(dev); > unsigned int channel = sd_attr->index; > - unsigned int val; > + int val; > int ret; > > - ret = kstrtouint(buf, 0, &val); > + ret = kstrtoint(buf, 0, &val); > if (ret) > return ret; > > - if (val == 0) > - return -EINVAL; > + val = clamp_val(val, 1, INT_MAX); > > ina->shunt_resistors[channel] = val; > > -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c index d055b6a2266b..e6b49500c52a 100644 --- a/drivers/hwmon/ina3221.c +++ b/drivers/hwmon/ina3221.c @@ -95,7 +95,7 @@ static const unsigned int register_channel[] = { struct ina3221_data { struct regmap *regmap; struct regmap_field *fields[F_MAX_FIELDS]; - unsigned int shunt_resistors[INA3221_NUM_CHANNELS]; + int shunt_resistors[INA3221_NUM_CHANNELS]; }; static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg, @@ -155,7 +155,7 @@ static ssize_t ina3221_show_current(struct device *dev, struct ina3221_data *ina = dev_get_drvdata(dev); unsigned int reg = sd_attr->index; unsigned int channel = register_channel[reg]; - unsigned int resistance_uo = ina->shunt_resistors[channel]; + int resistance_uo = ina->shunt_resistors[channel]; int val, current_ma, voltage_nv, ret; ret = ina3221_read_value(ina, reg, &val); @@ -176,7 +176,7 @@ static ssize_t ina3221_set_current(struct device *dev, struct ina3221_data *ina = dev_get_drvdata(dev); unsigned int reg = sd_attr->index; unsigned int channel = register_channel[reg]; - unsigned int resistance_uo = ina->shunt_resistors[channel]; + int resistance_uo = ina->shunt_resistors[channel]; int val, current_ma, voltage_uv, ret; ret = kstrtoint(buf, 0, ¤t_ma); @@ -223,15 +223,14 @@ static ssize_t ina3221_set_shunt(struct device *dev, struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr); struct ina3221_data *ina = dev_get_drvdata(dev); unsigned int channel = sd_attr->index; - unsigned int val; + int val; int ret; - ret = kstrtouint(buf, 0, &val); + ret = kstrtoint(buf, 0, &val); if (ret) return ret; - if (val == 0) - return -EINVAL; + val = clamp_val(val, 1, INT_MAX); ina->shunt_resistors[channel] = val;
The result of an integer divide by an unsigned is undefined. This causes unexpected results when writing negative values into the limit registers. Maintain the shunt_resistors variables as signed integer to avoid the problem. Also, for simplicity and ease of use, clamp shunt resistor value on writes instead of rejecting bad values. Cc: Andrew F. Davis <afd@ti.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> --- drivers/hwmon/ina3221.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)