[PATCH] platform/x86/intel-uncore-freq: Fail module load when plat_info is NULL

[Srinivas Pandruvada]

Address a Smatch static checker warning regarding an unchecked
dereference in the function call:
set_cdie_id(i, cluster_info, plat_info)
when plat_info is NULL.

Instead of addressing this one case, in general if plat_info is NULL
then it can cause other issues. For example in a two package system it
will give warning for duplicate sysfs entry as package ID will be always
zero for both packages when creating string for attribute group name.

plat_info is derived from TPMI ID TPMI_BUS_INFO, which is integral to
the core TPMI design. Therefore, it should not be NULL on a production
platform. Consequently, the module should fail to load if plat_info is
NULL.

Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Closes: https://lore.kernel.org/platform-driver-x86/aEKvGCLd1qmX04Tc@stanley.mountain/T/#u
Fixes: 8a54e2253e4c ("platform/x86/intel-uncore-freq: Uncore frequency control via TPMI")
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
 .../x86/intel/uncore-frequency/uncore-frequency-tpmi.c   | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c
index 1c7b2f2716ca..44d9948ed224 100644
--- a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c
+++ b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c
@@ -511,10 +511,13 @@ static int uncore_probe(struct auxiliary_device *auxdev, const struct auxiliary_
 
 	/* Get the package ID from the TPMI core */
 	plat_info = tpmi_get_platform_data(auxdev);
-	if (plat_info)
-		pkg = plat_info->package_id;
-	else
+	if (unlikely(!plat_info)) {
 		dev_info(&auxdev->dev, "Platform information is NULL\n");
+		ret = -ENODEV;
+		goto err_rem_common;
+	}
+
+	pkg = plat_info->package_id;
 
 	for (i = 0; i < num_resources; ++i) {
 		struct tpmi_uncore_power_domain_info *pd_info;
-- 
2.49.0