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SubjectRe: [PATCH v2] device property: fix of node refcount leak in fwnode_graph_get_next_endpoint()
On Tue, Nov 22, 2022 at 08:00:39PM +0800, Yang Yingliang wrote:
> The 'parent' returned by fwnode_graph_get_port_parent()
> with refcount incremented when 'prev' is not null, it

NULL

> 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().

...

> 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)
> + if (ep) {
> + fwnode_handle_put(port_parent);
> return ep;
> + }
>
> - return fwnode_graph_get_next_endpoint(parent->secondary, NULL);
> + ep = fwnode_graph_get_next_endpoint(parent->secondary, NULL);
> + fwnode_handle_put(port_parent);
> + return ep;

It seems too complicated for the simple fix.

As I said, just drop const qualifier and add fwnode_handle_get() in the 'else'
branch. This will allow you to drop if (prev) at the end.

--
With Best Regards,
Andy Shevchenko


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