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

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

[Yang Yingliang]

I got the following report:

  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>
---
 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);
 }
 
-- 
2.25.1

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

[Greg KH]

On Fri, Nov 18, 2022 at 10:18:50PM +0800, Yang Yingliang wrote:
> I got the following report:
> 
>   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

report from what?  What generates this?

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

[Yang Yingliang]

On 2022/11/19 1:57, Greg KH wrote:
> On Fri, Nov 18, 2022 at 10:18:50PM +0800, Yang Yingliang wrote:
>> I got the following report:
>>
>>    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
> report from what?  What generates this?
I got this report while doing loading device (mt6370-tcpc) test
with CONFIG_OF_UNITTEST and CONFIG_OF_DYNAMIC enabled.

Thanks,
Yang
>
> .

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

[Greg KH]

On Sat, Nov 19, 2022 at 03:47:33PM +0800, Yang Yingliang wrote:
> 
> On 2022/11/19 1:57, Greg KH wrote:
> > On Fri, Nov 18, 2022 at 10:18:50PM +0800, Yang Yingliang wrote:
> > > I got the following report:
> > > 
> > >    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
> > report from what?  What generates this?
> I got this report while doing loading device (mt6370-tcpc) test
> with CONFIG_OF_UNITTEST and CONFIG_OF_DYNAMIC enabled.

Please include that in the information in the changelog text and
resubmit a v2.

thanks,

greg k-h