Re: [PATCH v3] device property: fix of node refcount leak in fwnode_graph_get_next_endpoint()

Daniel Scally
2022-11-25T09:33:06Z

Hello

On 23/11/2022 13:31, Andy Shevchenko wrote:
> On Wed, Nov 23, 2022 at 10:25:42AM +0800, Yang Yingliang wrote:
>> The 'parent' returned by fwnode_graph_get_port_parent()
>> with refcount incremented when 'prev' is not NULL, it
>> needs be put when finish using it.
>>
>> Because the parent is const, introduce a new variable to
>> store the returned fwnode, then put it before returning
>> from fwnode_graph_get_next_endpoint().
> To me this looks good enough. Not sure if Dan has a chance (time) to look at
> this, though. And maybe even test...
>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Apologies; didn't notice this earlier. I will look at and test this today

>
>> Fixes: b5b41ab6b0c1 ("device property: Check fwnode->secondary in fwnode_graph_get_next_endpoint()")
>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
>> ---
>> v2 -> v3:
>> Add a out label.
>>
>> v1 -> v2:
>> Introduce a new variable to store the returned fwnode.
>> ---
>> drivers/base/property.c | 18 ++++++++++++------
>> 1 file changed, 12 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/base/property.c b/drivers/base/property.c
>> index 2a5a37fcd998..7f338cb4fb7b 100644
>> --- a/drivers/base/property.c
>> +++ b/drivers/base/property.c
>> @@ -989,26 +989,32 @@ struct fwnode_handle *
>> fwnode_graph_get_next_endpoint(const struct fwnode_handle *fwnode,
>> struct fwnode_handle *prev)
>> {
>> + struct fwnode_handle *ep, *port_parent = NULL;
>> const struct fwnode_handle *parent;
>> - struct fwnode_handle *ep;
>>
>> /*
>> * If this function is in a loop and the previous iteration returned
>> * an endpoint from fwnode->secondary, then we need to use the secondary
>> * as parent rather than @fwnode.
>> */
>> - if (prev)
>> - parent = fwnode_graph_get_port_parent(prev);
>> - else
>> + if (prev) {
>> + port_parent = fwnode_graph_get_port_parent(prev);
>> + parent = port_parent;
>> + } else {
>> parent = fwnode;
>> + }
>> if (IS_ERR_OR_NULL(parent))
>> return NULL;
>>
>> ep = fwnode_call_ptr_op(parent, graph_get_next_endpoint, prev);
>> if (ep)
>> - return ep;
>> + goto out_put_port_parent;
>> +
>> + ep = fwnode_graph_get_next_endpoint(parent->secondary, NULL);
>>
>> - return fwnode_graph_get_next_endpoint(parent->secondary, NULL);
>> +out_put_port_parent:
>> + fwnode_handle_put(port_parent);
>> + return ep;
>> }
>> EXPORT_SYMBOL_GPL(fwnode_graph_get_next_endpoint);
>>
>> --
>> 2.25.1
>>