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

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The newly added error path for DMI match failure introduces an I/O resource leak.
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commit 6d1770785fa851d42148760f539b79225f6680d7
Author: Kean <rh_king@163.com>

hwmon: lenovo-ec-sensors: Fix NULL pointer dereference when DMI match fails

This commit adds a check to ensure dmi_first_match() does not return NULL
before accessing its driver_data. If no match is found, the probe function
now gracefully returns -ENODEV to prevent a kernel oops.

> diff --git a/drivers/hwmon/lenovo-ec-sensors.c b/drivers/hwmon/lenovo-ec-sensors.c
> index 6cd83c378f091..10fc0376cb7f7 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;

Does this new error path leak the I/O region requested earlier in the probe
function?

Looking earlier in lenovo_ec_probe(), request_region() is called to reserve
the I/O ports:

drivers/hwmon/lenovo-ec-sensors.c:lenovo_ec_probe() {
        ...
        if (!request_region(IO_REGION_START, IO_REGION_LENGTH, "LNV-WKS")) {
                pr_err(":request fail\n");
                return -EIO;
        }
        ...
}

Other error paths in the function explicitly call release_region() before
returning, but this newly added return does not.

I note that this issue is resolved later in the series by the commit
"hwmon: lenovo-ec-sensors: Use devm_request_region for automatic cleanup".

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Sashiko AI review · https://sashiko.dev/#/patchset/20260514011411.4167069-1-rh_king@163.com?part=2