diff options
| author | Luiz Angelo Daros de Luca <luizluca@gmail.com> | 2026-07-27 21:22:19 -0300 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2026-07-27 17:55:07 -0700 |
| commit | cb0b7f9c43b0abbd422a7e4c2c85e91db429207c (patch) | |
| tree | 3d5a3304190504cb5907425cd8131a44ddc1bab3 | |
| parent | 05270bd38d9bf88a2f4c212246a8fa29f4032078 (diff) | |
hwmon: (adt7470) Fix busy-loop and I2C flooding in update thread
When userspace configures 'auto_update_interval' to 0 via sysfs, the
background kthread executes schedule_timeout_interruptible(0), which
returns immediately.
If 'num_temp_sensors' is concurrently or previously set to 0, the
msleep_interruptible() delay inside adt7470_read_temperatures() also
becomes 0. This combination forces the background thread into a tight,
unbounded busy-loop, hogging the CPU and flooding the I2C bus with a
continuous stream of transactions.
Fix this vulnerability by raising the lower limit of the clamp_val in
auto_update_interval_store() from 0 to 500 milliseconds. This guarantees
a reasonable minimum sleep window between sensor updates, protecting the
system from intentional or accidental I2C bus denial of service.
Reported-by: sashiko-bot@kernel.org
Closes: https://lore.kernel.org/r/20260716213252.EACA71F000E9@smtp.kernel.org
Fixes: 89fac11cb3e7 ("adt7470: make automatic fan control really work")
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Link: https://lore.kernel.org/r/20260727-adt7470_fixes-v2-3-598e38a46ba6@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
| -rw-r--r-- | drivers/hwmon/adt7470.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c index 62ec68ea0a40..0b19b0925d1c 100644 --- a/drivers/hwmon/adt7470.c +++ b/drivers/hwmon/adt7470.c @@ -509,7 +509,7 @@ static ssize_t auto_update_interval_store(struct device *dev, if (kstrtol(buf, 10, &temp)) return -EINVAL; - temp = clamp_val(temp, 0, 60000); + temp = clamp_val(temp, 500, 60000); mutex_lock(&data->lock); data->auto_update_interval = temp; |