5.4-stable review patch. If anyone has any objections, please let me know.
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From: Guenter Roeck linux@roeck-us.net
[ Upstream commit cbf7467828cd4ec7ceac7a8b5b5ddb2f69f07b0e ]
Using DIV_ROUND_CLOSEST() on an unbound value can result in underflows. Indeed, module test scripts report:
temp1_max: Suspected underflow: [min=0, read 255000, written -9223372036854775808] temp1_crit: Suspected underflow: [min=0, read 255000, written -9223372036854775808]
Fix by introducing an extra set of clamping.
Fixes: 5372d2d71c46 ("hwmon: Driver for Maxim MAX6697 and compatibles") Reviewed-by: Tzung-Bi Shih tzungbi@kernel.org Signed-off-by: Guenter Roeck linux@roeck-us.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/hwmon/max6697.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/hwmon/max6697.c b/drivers/hwmon/max6697.c index 64122eb38060d..cfd5815e60dfa 100644 --- a/drivers/hwmon/max6697.c +++ b/drivers/hwmon/max6697.c @@ -305,6 +305,7 @@ static ssize_t temp_store(struct device *dev, return ret;
mutex_lock(&data->update_lock); + temp = clamp_val(temp, -1000000, 1000000); /* prevent underflow */ temp = DIV_ROUND_CLOSEST(temp, 1000) + data->temp_offset; temp = clamp_val(temp, 0, data->type == max6581 ? 255 : 127); data->temp[nr][index] = temp;