[PATCH AUTOSEL 5.4 20/22] hwmon: (w83627ehf) Fix underflows seen when writing limit attributes

Sasha Levin
2024-08-01T00:40:16Z

From: Guenter Roeck <linux@roeck-us.net>

[ Upstream commit 5c1de37969b7bc0abcb20b86e91e70caebbd4f89 ]

DIV_ROUND_CLOSEST() after kstrtol() results in an underflow if a large
negative number such as -9223372036854775808 is provided by the user.
Fix it by reordering clamp_val() and DIV_ROUND_CLOSEST() operations.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwmon/w83627ehf.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/w83627ehf.c b/drivers/hwmon/w83627ehf.c
index eb171d15ac489..e4e5bb9115584 100644
--- a/drivers/hwmon/w83627ehf.c
+++ b/drivers/hwmon/w83627ehf.c
@@ -1506,7 +1506,7 @@ store_target_temp(struct device *dev, struct device_attribute *attr,
if (err < 0)
return err;

- val = clamp_val(DIV_ROUND_CLOSEST(val, 1000), 0, 127);
+ val = DIV_ROUND_CLOSEST(clamp_val(val, 0, 127000), 1000);

mutex_lock(&data->update_lock);
data->target_temp[nr] = val;
@@ -1532,7 +1532,7 @@ store_tolerance(struct device *dev, struct device_attribute *attr,
return err;

/* Limit the temp to 0C - 15C */
- val = clamp_val(DIV_ROUND_CLOSEST(val, 1000), 0, 15);
+ val = DIV_ROUND_CLOSEST(clamp_val(val, 0, 15000), 1000);

mutex_lock(&data->update_lock);
if (sio_data->kind == nct6775 || sio_data->kind == nct6776) {
--
2.43.0