Re: [PATCH v2] usb: roles: fix of node refcount leak in usb_role_switch_is_parent()

[Yang Yingliang <yangyingliang@huawei.com>]

On 2022/11/21 15:55, Chunfeng Yun (云春峰) wrote:
> Hi Yingliang,
>
> On Sat, 2022-11-19 at 17:15 +0800, Yang Yingliang wrote:
>> I got the following report while doing device(mt6370-tcpc) load
>> test with CONFIG_OF_UNITTEST and CONFIG_OF_DYNAMIC enabled:
>>
>>    OF: ERROR: memory leak, expected refcount 1 instead of 2,
>>    of_node_get()/of_node_put() unbalanced - destroy cset entry:
>>    attach overlay node /i2c/pmic@34
>>
>> The 'parent' returned by fwnode_get_parent() with refcount
>> incremented.
>> it needs be put after using.
>>
>> Fixes: 6fadd72943b8 ("usb: roles: get usb-role-switch from parent")
>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
>> ---
>> v1 -> v2:
>>    Add description to how is the report generated.
>> ---
>>   drivers/usb/roles/class.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
>> index dfaed7eee94f..289950e5fcfb 100644
>> --- a/drivers/usb/roles/class.c
>> +++ b/drivers/usb/roles/class.c
>> @@ -106,10 +106,14 @@ usb_role_switch_is_parent(struct fwnode_handle
>> *fwnode)
>>   	struct fwnode_handle *parent = fwnode_get_parent(fwnode);
>>   	struct device *dev;
>>   
>> -	if (!parent || !fwnode_property_present(parent, "usb-role-
>> switch"))
>> +	if (!parent || !fwnode_property_present(parent, "usb-role-
>> switch")) {
>> +		if (parent)
>> +			fwnode_handle_put(parent);
>>   		return NULL;
>> +	}
>>   
>>   	dev = class_find_device_by_fwnode(role_class, parent);
>> +	fwnode_handle_put(parent);
>>   	return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER);
>>   }
> Please use get_maintainer script to find who you should sent to after
> generating patches
>
> e.g.:
> ./scripts/get_maintainer.pl --no-rolestats 00* | gawk '{printf("
> --cc=\"%s\" ", $0)} END{printf("\n")}'
>
> Thanks
I used get_maintainer.pl to get the maintainer in Linux 6.1-rc5 and sent 
the patch.

./scripts/get_maintainer.pl 
0001-usb-roles-fix-of-node-refcount-leak-in-usb_role_swit.patch
Greg Kroah-Hartman <gregkh@linuxfoundation.org> (supporter:USB 
SUBSYSTEM,blamed_fixes:1/1=100%)
Chunfeng Yun <chunfeng.yun@mediatek.com> (blamed_fixes:1/1=100%)
linux-usb@vger.kernel.org (open list:USB SUBSYSTEM)
linux-kernel@vger.kernel.org (open list)

Thanks,
Yang
>
>>