[PATCH] platform/x86: dell-sysman: Fix reference leak

[PATCH] platform/x86: dell-sysman: Fix reference leak

[Armin Wolf]

If a duplicate attribute is found using kset_find_obj(),
a reference to that attribute is returned. This means
that we need to dispose it accordingly. Use kobject_put()
to dispose the duplicate attribute in such a case.

Compile-tested only.

Fixes: e8a60aa7404b ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
 drivers/platform/x86/dell/dell-wmi-sysman/sysman.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c b/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c
index b68dd11cb892..b929b4f82420 100644
--- a/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c
+++ b/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c
@@ -393,6 +393,7 @@ static int init_bios_attributes(int attr_type, const char *guid)
 	struct kobject *attr_name_kobj; //individual attribute names
 	union acpi_object *obj = NULL;
 	union acpi_object *elements;
+	struct kobject *duplicate;
 	struct kset *tmp_set;
 	int min_elements;

@@ -451,9 +452,11 @@ static int init_bios_attributes(int attr_type, const char *guid)
 		else
 			tmp_set = wmi_priv.main_dir_kset;

-		if (kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer)) {
-			pr_debug("duplicate attribute name found - %s\n",
-				elements[ATTR_NAME].string.pointer);
+		duplicate = kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer);
+		if (duplicate) {
+			pr_debug("Duplicate attribute name found - %s\n",
+				 elements[ATTR_NAME].string.pointer);
+			kobject_put(duplicate);
 			goto nextobj;
 		}

--
2.39.2

Re: [PATCH] platform/x86: dell-sysman: Fix reference leak

[Hans de Goede]

Hi,

On 8/5/23 07:36, Armin Wolf wrote:
> If a duplicate attribute is found using kset_find_obj(),
> a reference to that attribute is returned. This means
> that we need to dispose it accordingly. Use kobject_put()
> to dispose the duplicate attribute in such a case.
> 
> Compile-tested only.
> 
> Fixes: e8a60aa7404b ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>

Thank you for your patch, I've applied this patch to my review-hans 
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans



> ---
>  drivers/platform/x86/dell/dell-wmi-sysman/sysman.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c b/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c
> index b68dd11cb892..b929b4f82420 100644
> --- a/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c
> +++ b/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c
> @@ -393,6 +393,7 @@ static int init_bios_attributes(int attr_type, const char *guid)
>  	struct kobject *attr_name_kobj; //individual attribute names
>  	union acpi_object *obj = NULL;
>  	union acpi_object *elements;
> +	struct kobject *duplicate;
>  	struct kset *tmp_set;
>  	int min_elements;
> 
> @@ -451,9 +452,11 @@ static int init_bios_attributes(int attr_type, const char *guid)
>  		else
>  			tmp_set = wmi_priv.main_dir_kset;
> 
> -		if (kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer)) {
> -			pr_debug("duplicate attribute name found - %s\n",
> -				elements[ATTR_NAME].string.pointer);
> +		duplicate = kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer);
> +		if (duplicate) {
> +			pr_debug("Duplicate attribute name found - %s\n",
> +				 elements[ATTR_NAME].string.pointer);
> +			kobject_put(duplicate);
>  			goto nextobj;
>  		}
> 
> --
> 2.39.2
>