This is a note to let you know that I've just added the patch titled
hwmon: (f71882fg) prevent possible division by zero
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
hwmon-f71882fg-prevent-possible-division-by-zero.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8cd21dbb56178108a3ec637c77027a18fe4d28a6
Author: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>
Date: Wed May 10 07:35:37 2023 -0700
hwmon: (f71882fg) prevent possible division by zero
[ Upstream commit 0babf89c9cca7e074d6e59893e462e4886f481cc ]
In the unlikely event that something goes wrong with the device and
its registers, the fan_from_reg() function may return 0. This value
will cause a division-by-zero error in the show_pwm() function.
To prevent this, test the value of
fan_from_reg(data->fan_full_speed[nr]) against 0 before performing
the division. If the division-by-zero error is avoided, assign 0 to
the val variable.
Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.
Fixes: df9ec2dae094 ("hwmon: (f71882fg) Reorder symbols to get rid of a few forward declarations")
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230510143537.145060-1-n.zhandarovich@xxxxxxxxxx
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/hwmon/f71882fg.c b/drivers/hwmon/f71882fg.c
index 70121482a6173..27207ec6f7feb 100644
--- a/drivers/hwmon/f71882fg.c
+++ b/drivers/hwmon/f71882fg.c
@@ -1096,8 +1096,11 @@ static ssize_t show_pwm(struct device *dev,
val = data->pwm[nr];
else {
/* RPM mode */
- val = 255 * fan_from_reg(data->fan_target[nr])
- / fan_from_reg(data->fan_full_speed[nr]);
+ if (fan_from_reg(data->fan_full_speed[nr]))
+ val = 255 * fan_from_reg(data->fan_target[nr])
+ / fan_from_reg(data->fan_full_speed[nr]);
+ else
+ val = 0;
}
mutex_unlock(&data->update_lock);
return sprintf(buf, "%d\n", val);
