linux-kernel - [PATCH v2 2/2] platform/x86: hp-bioscfg: Fix reference leak

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Date:   Mon, 25 Sep 2023 15:25:57 +0200
From:   Armin Wolf <W_Armin@....de>
To:     markpearson@...ovo.com, jorge.lopez2@...com
Cc:     hdegoede@...hat.com, markgross@...nel.org,
        ilpo.jarvinen@...ux.intel.com, platform-driver-x86@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/2] platform/x86: hp-bioscfg: Fix reference leak

If a duplicate attribute is found using kset_find_obj(), a reference
to that attribute is returned which needs to be disposed accordingly
using kobject_put(). Use kobject_put() to dispose the duplicate
attribute in such a case.
As a side note, a very similar bug was fixed in
commit 7295a996fdab ("platform/x86: dell-sysman: Fix reference leak"),
so it seems that the bug was copied from that driver.

Compile-tested only.

Fixes: a34fc329b189 ("platform/x86: hp-bioscfg: bioscfg")
Suggested-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Signed-off-by: Armin Wolf <W_Armin@....de>
---
Changes in v2:
- add patch
---
 drivers/platform/x86/hp/hp-bioscfg/bioscfg.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
index 8c4f9e12f018..0c83e66f8d0b 100644
--- a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
+++ b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
@@ -659,7 +659,7 @@ static int hp_init_bios_package_attribute(enum hp_wmi_data_type attr_type,
 					  const char *guid, int min_elements,
 					  int instance_id)
 {
-	struct kobject *attr_name_kobj;
+	struct kobject *attr_name_kobj, *duplicate;
 	union acpi_object *elements;
 	struct kset *temp_kset;

@@ -704,8 +704,11 @@ static int hp_init_bios_package_attribute(enum hp_wmi_data_type attr_type,
 	}

 	/* All duplicate attributes found are ignored */
-	if (kset_find_obj(temp_kset, str_value)) {
+	duplicate = kset_find_obj(temp_kset, str_value);
+	if (duplicate) {
 		pr_debug("Duplicate attribute name found - %s\n", str_value);
+		/* kset_find_obj() returns a reference */
+		kobject_put(duplicate);
 		goto pack_attr_exit;
 	}

@@ -768,7 +771,7 @@ static int hp_init_bios_buffer_attribute(enum hp_wmi_data_type attr_type,
 					 const char *guid, int min_elements,
 					 int instance_id)
 {
-	struct kobject *attr_name_kobj;
+	struct kobject *attr_name_kobj, *duplicate;
 	struct kset *temp_kset;
 	char str[MAX_BUFF_SIZE];

@@ -794,8 +797,11 @@ static int hp_init_bios_buffer_attribute(enum hp_wmi_data_type attr_type,
 		temp_kset = bioscfg_drv.main_dir_kset;

 	/* All duplicate attributes found are ignored */
-	if (kset_find_obj(temp_kset, str)) {
+	duplicate = kset_find_obj(temp_kset, str);
+	if (duplicate) {
 		pr_debug("Duplicate attribute name found - %s\n", str);
+		/*kset_find_obj() returns a reference */
+		kobject_put(duplicate);
 		goto buff_attr_exit;
 	}

--
2.39.2