hwmon: (nct7802) Fix overflows seen when writing into limit attributes (c0d04e91) · Commits · 戴 / test

Fix overflows seen when writing voltage and temperature limit attributes. The value passed to DIV_ROUND_CLOSEST() needs to be clamped, and the value parameter passed to nct7802_write_fan_min() is an unsigned long. Also, writing values larger than 2700000 into a fan limit attribute results in writing 0 into the chip's limit registers. The exact behavior when writing this value is unspecified. For consistency, report a limit of 1350000 if the chip register reads 0. This may be wrong, and the chip behavior should be verified with the actual chip, but it is better than reporting a value of 0 (which, when written, results in writing a value of 0x1fff into the chip register). Fixes: ("hwmon: Driver for Nuvoton NCT7802Y") Reviewed-by:

Jean Delvare <jdelvare@suse.de> Signed-off-by:

Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/nct7802.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -259,13 +259,15 @@ static int nct7802_read_fan_min(struct nct7802_data *data, u8 reg_fan_low,
		ret = 0;
		else if (ret)
		ret = DIV_ROUND_CLOSEST(1350000U, ret);
		else
		ret = 1350000U;
		abort:
		mutex_unlock(&data->access_lock);
		return ret;
		}

		static int nct7802_write_fan_min(struct nct7802_data *data, u8 reg_fan_low,
		u8 reg_fan_high, unsigned int limit)
		u8 reg_fan_high, unsigned long limit)
		{
		int err;

		@@ -326,8 +328,8 @@ static int nct7802_write_voltage(struct nct7802_data *data, int nr, int index,
		int shift = 8 - REG_VOLTAGE_LIMIT_MSB_SHIFT[index - 1][nr];
		int err;

		voltage = clamp_val(voltage, 0, 0x3ff * nct7802_vmul[nr]);
		voltage = DIV_ROUND_CLOSEST(voltage, nct7802_vmul[nr]);
		voltage = clamp_val(voltage, 0, 0x3ff);

		mutex_lock(&data->access_lock);
		err = regmap_write(data->regmap,
		@@ -402,7 +404,7 @@ static ssize_t store_temp(struct device dev, struct device_attribute attr,
		if (err < 0)
		return err;

		val = clamp_val(DIV_ROUND_CLOSEST(val, 1000), -128, 127);
		val = DIV_ROUND_CLOSEST(clamp_val(val, -128000, 127000), 1000);

		err = regmap_write(data->regmap, nr, val & 0xff);
		return err ? : count;

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