linux-kernel - [PATCH] platform/x86/intel/tpmi: Fix double free reported by Smatch

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Message-Id: <20230227140614.2913474-1-srinivas.pandruvada@linux.intel.com>
Date:   Mon, 27 Feb 2023 06:06:14 -0800
From:   Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To:     hdegoede@...hat.com, markgross@...nel.org
Cc:     platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Dan Carpenter <error27@...il.com>
Subject: [PATCH] platform/x86/intel/tpmi: Fix double free reported by Smatch

Fix warning:
drivers/platform/x86/intel/tpmi.c:253 tpmi_create_device()
	warn: 'feature_vsec_dev' was already freed.

If there is some error, feature_vsec_dev memory is freed as part
of resource managed call intel_vsec_add_aux(). So, additional
kfree() call is not required.

Reordered res allocation and feature_vsec_dev, so that on error
only res is freed.

Reported-by: Dan Carpenter <error27@...il.com>
Link: https://lore.kernel.org/platform-driver-x86/Y%2FxYR7WGiPayZu%2FR@kili/T/#u
Fixes: 47731fd2865f ("platform/x86/intel: Intel TPMI enumeration driver")
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
---
 drivers/platform/x86/intel/tpmi.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/platform/x86/intel/tpmi.c b/drivers/platform/x86/intel/tpmi.c
index c60733261c89..c999732b0f1e 100644
--- a/drivers/platform/x86/intel/tpmi.c
+++ b/drivers/platform/x86/intel/tpmi.c
@@ -209,14 +209,14 @@ static int tpmi_create_device(struct intel_tpmi_info *tpmi_info,
 	if (!name)
 		return -EOPNOTSUPP;
 
-	feature_vsec_dev = kzalloc(sizeof(*feature_vsec_dev), GFP_KERNEL);
-	if (!feature_vsec_dev)
+	res = kcalloc(pfs->pfs_header.num_entries, sizeof(*res), GFP_KERNEL);
+	if (!res)
 		return -ENOMEM;
 
-	res = kcalloc(pfs->pfs_header.num_entries, sizeof(*res), GFP_KERNEL);
-	if (!res) {
+	feature_vsec_dev = kzalloc(sizeof(*feature_vsec_dev), GFP_KERNEL);
+	if (!feature_vsec_dev) {
 		ret = -ENOMEM;
-		goto free_vsec;
+		goto free_res;
 	}
 
 	snprintf(feature_id_name, sizeof(feature_id_name), "tpmi-%s", name);
@@ -239,6 +239,8 @@ static int tpmi_create_device(struct intel_tpmi_info *tpmi_info,
 	/*
 	 * intel_vsec_add_aux() is resource managed, no explicit
 	 * delete is required on error or on module unload.
+	 * feature_vsec_dev memory is also freed as part of device
+	 * delete.
 	 */
 	ret = intel_vsec_add_aux(vsec_dev->pcidev, &vsec_dev->auxdev.dev,
 				 feature_vsec_dev, feature_id_name);
@@ -249,8 +251,6 @@ static int tpmi_create_device(struct intel_tpmi_info *tpmi_info,
 
 free_res:
 	kfree(res);
-free_vsec:
-	kfree(feature_vsec_dev);
 
 	return ret;
 }
-- 
2.39.1