Re: [PATCH v3] usb: roles: fix of node refcount leak in usb_role_switch_is_parent()

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Tue, Nov 22, 2022 at 04:47:00PM +0800, Yang Yingliang wrote:
> 
> On 2022/11/22 16:33, Heikki Krogerus wrote:
> > Hi,
> > 
> > On Mon, Nov 21, 2022 at 10:46:20PM +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")
> > > Suggested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > That's not the appropriate tag in this case. I have not suggested
> > this patch.
> > 
> > > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> > > ---
> > > v2 -> v3:
> > >    Remove not needed null pointer check.
> > > 
> > > v1 -> v2:
> > >    Add description to how is the report generated.
> > > ---
> > >   drivers/usb/roles/class.c | 5 ++++-
> > >   1 file changed, 4 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
> > > index dfaed7eee94f..0650295f261c 100644
> > > --- a/drivers/usb/roles/class.c
> > > +++ b/drivers/usb/roles/class.c
> > > @@ -106,10 +106,13 @@ 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")) {
> > Please change that as well like I proposed earlier:
> > 
> > 	if (!fwnode_property_present(parent, "usb-role-switch")) {
> > 
> > You don't need to check the parent separately.
> Yes, fwnode_property_present() has already checked the parent, the parent
> check can be removed.
> Need I add your suggest tag when I send v4 to change it as above.

No. I still have not suggested this patch. I've only commented it.

thanks,

-- 
heikki