From: Michael Bommarito Date: Wed, 13 May 2026 23:38:38 +0000 (-0400) Subject: net: hsr: defer node table free until after RCU readers X-Git-Tag: v7.1-rc5~40^2~62 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=aaec7096f9961eb223b5b149abe9495525c205d9;p=thirdparty%2Flinux.git 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(). Fixes: b9a1e627405d ("hsr: implement dellink to clean up resources") Cc: stable@vger.kernel.org # v5.3+ Signed-off-by: Michael Bommarito Link: https://patch.msgid.link/20260513233838.3064715-2-michael.bommarito@gmail.com Signed-off-by: Jakub Kicinski --- diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c index 124619920d386..b514e43766eff 100644 --- a/net/hsr/hsr_framereg.c +++ b/net/hsr/hsr_framereg.c @@ -163,8 +163,8 @@ void hsr_del_nodes(struct list_head *node_db) struct hsr_node *tmp; list_for_each_entry_safe(node, tmp, node_db, mac_list) { - list_del(&node->mac_list); - hsr_free_node(node); + list_del_rcu(&node->mac_list); + call_rcu(&node->rcu_head, hsr_free_node_rcu); } }