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

[Kean <rh_king@163.com>]

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@163.com>

Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
---
 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:
-- 
2.47.3