Re: [PATCH 2/3] hwmon: lenovo-ec-sensors: Fix NULL pointer dereference when DMI match fails

[Guenter Roeck]

On Thu, May 14, 2026 at 09:14:10AM +0800, Kean wrote:
> dmi_first_match() returns NULL if the running system does not match any
> entry in thinkstation_dmi_table. Without a NULL check, the subsequent
> dmi_id->driver_data access dereferences a NULL pointer, causing a kernel
> oops or panic.
> 
> Add a NULL check and return -ENODEV to gracefully fail the probe when
> the driver is loaded on an unsupported platform.
> 
> Signed-off-by: Kean <rh_king@xxxxxxx>
> 
> Reviewed-by: Mark Pearson <mpearson-lenovo@xxxxxxxxx>

ERROR: trailing whitespace
#104: FILE: drivers/hwmon/lenovo-ec-sensors.c:540:
+^Iif ((inb_p(MCHP_EMI0_EC_DATA_BYTE0) != 'M') || $

ERROR: trailing whitespace
#105: FILE: drivers/hwmon/lenovo-ec-sensors.c:541:
+^I    (inb_p(MCHP_EMI0_EC_DATA_BYTE1) != 'C') || $

total: 2 errors, 0 warnings, 0 checks, 12 lines checked

> ---
>  drivers/hwmon/lenovo-ec-sensors.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/hwmon/lenovo-ec-sensors.c b/drivers/hwmon/lenovo-ec-sensors.c
> index a32b1f2c6a3a..b0f2a04ce679 100644
> --- a/drivers/hwmon/lenovo-ec-sensors.c
> +++ b/drivers/hwmon/lenovo-ec-sensors.c
> @@ -546,6 +546,8 @@ static int lenovo_ec_probe(struct platform_device *pdev)
>  	}
>  
>  	dmi_id = dmi_first_match(thinkstation_dmi_table);
> +	if (!dmi_id)
> +		return -ENODEV;
>  
>  	switch ((long)dmi_id->driver_data) {
>  	case 0: