CVE-2026-64123net: hsr: defer node table free until after RCU readers

Official description

In the Linux kernel, the following vulnerability has been resolved: net: hsr: defer node table free until after RCU readers HSR node-list and node-status generic-netlink operations run under rcu_read_lock(). They walk hsr->node_db through hsr_get_next_node() and hsr_get_node_data(), but RTM_DELLINK teardown removes the same node table with plain list_del() and frees each node immediately. That lets a generic-netlink reader hold a struct hsr_node pointer across hsr_dellink(). In a KASAN build, widening the reader window after hsr_get_next_node() obtains the node reproduces a slab-use-after-free when the reader copies node->macaddress_A; the freeing stack is hsr_del_nodes() from hsr_dellink(). Use list_del_rcu() and defer the free through the existing hsr_free_node_rcu() callback. This matches the lifetime rule used by the HSR prune paths, which already delete nodes with list_del_rcu() and call_rcu().

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/0ea70fb46940620848c08d9d399455c9e82fecdb
• https://git.kernel.org/stable/c/8be6685cdd1255bcc85f9b59e4bfc313aefc5c1b
• https://git.kernel.org/stable/c/c5580114e0492bcd2e0a37613ed4c311e3fa3d4d
• https://git.kernel.org/stable/c/7713f4aafb577ff49fa67f0488d9c7dddc64d6ce
• https://git.kernel.org/stable/c/6324423a8e6591f41a16c09a8f9a84e554ac147c
• https://git.kernel.org/stable/c/48d09dea506de667eb55f939bf98eec721effbdb
• https://git.kernel.org/stable/c/8c3af18bb0d7c921a5219194037509463eb2ffde
• https://git.kernel.org/stable/c/aaec7096f9961eb223b5b149abe9495525c205d9