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

From: Yang Yingliang
Date: Tue Nov 22 2022 - 21:27:46 EST


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().

Fixes: b5b41ab6b0c1 ("device property: Check fwnode->secondary in fwnode_graph_get_next_endpoint()")
Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
---
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