[PATCH v3] platform/x86: lenovo: wmi-other: Fix uninitialized variable in lwmi_om_hwmon_write()

From: Yufei CHENG

Date: Sun Apr 26 2026 - 12:50:56 EST


When the flag relax_fan_constraint is set, local variable 'raw'
is never assigned, and lwmi_om_hwmon_write() will pass uninitialized
value to lwmi_om_fan_get_set() resulting in undefined behavior.

This flag allows user to bypass minimum fan RPM divisor rounding,
but assignment to 'raw' only happens in the non-relaxed path.
Fix by defaulting 'raw' to user provided 'val' in the else branch.

Fixes: 51ed34282f63 ("platform/x86: lenovo-wmi-other: Add HWMON for fan reporting/tuning")
Reviewed-by: Rong Zhang <i@xxxxxxxx>
Signed-off-by: Yufei CHENG <cd345al@xxxxxxxxx>
---
v3: fix broken format
v2: rewrite the title to be more specific

drivers/platform/x86/lenovo/wmi-other.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/platform/x86/lenovo/wmi-other.c b/drivers/platform/x86/lenovo/wmi-other.c
index 6040f45aa2b..6c2febe1a59 100644
--- a/drivers/platform/x86/lenovo/wmi-other.c
+++ b/drivers/platform/x86/lenovo/wmi-other.c
@@ -349,6 +349,8 @@ static int lwmi_om_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
*/
if (!relax_fan_constraint)
raw = val / LWMI_FAN_DIV * LWMI_FAN_DIV;
+ else
+ raw = val;

err = lwmi_om_fan_get_set(priv, channel, &raw, true);
if (err)
--
2.43.0