CVE-2026-89744

In the Linux kernel, the following vulnerability has been resolved:

device property: fix infinite loop in fwnode_for_each_child_node()

When iterate over children of a fwnode that has a secondary fwnode,

fwnode_get_next_child_node() can enter an infinite loop if the secondary

fwnode has more than one child.

Parent Child

(Primary fwnode) FWa: {FWa1, FWa2, FWa3}

(Secondary fwnode) FWb: {FWb1, FWb2}

In this case:

┌─> fwnode_get_next_child_node(FWa, FWa1)

│ - fwnode_call_ptr_op(FWa, get_next_child_node, FWa1) returns FWa2

│

│ ...

│

│ fwnode_get_next_child_node(FWa, FWa3)

│ - fwnode_call_ptr_op(FWa, get_next_child_node, FWa3) returns NULL

│ - fwnode_call_ptr_op(FWb, get_next_child_node, FWa3) returns FWb1

│

│ fwnode_get_next_child_node(FWa, FWb1)

│ - fwnode_call_ptr_op(FWa, get_next_child_node, FWb1) returns FWa1

└────┘

This cause fwnode_for_each_child_node() to loop indefinitely, reapeatedly

output {FWa1, FWa2, FWa3, FWb1, FWa1, ...}.

The root cause is that when the current child (FWb1) belongs to the

secondary fwnode, calling get_next_child_node() on the parimary fwnode

incorrectly returns the first child (FWa1) again instead of NULL.

Fix this by dynamically checking the parent fwnode of the current child

before calling get_next_child_node(). This approach follows the pattern

established in commit b5b41ab6b0c1 ("device property: Check

fwnode->secondary in fwnode_graph_get_next_endpoint()").