Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 070/101] hwmon: (nct7802) Fix overflows seen when writing into limit attributes | Date | Tue, 10 Jan 2017 14:37:23 +0100 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Guenter Roeck <linux@roeck-us.net>
commit c0d04e9112ad59d73f23f3b0f6726c5e798dfcbf upstream.
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: 3434f3783580 ("hwmon: Driver for Nuvoton NCT7802Y") Reviewed-by: Jean Delvare <jdelvare@suse.de> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/hwmon/nct7802.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/drivers/hwmon/nct7802.c +++ b/drivers/hwmon/nct7802.c @@ -259,13 +259,15 @@ static int nct7802_read_fan_min(struct n 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 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 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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