[PATCH net v5 2/2] tipc: fix node reference leak when defer work is already pending

[Weiming Shi <bestswngs@gmail.com>]

In tipc_node_write_unlock(), TIPC_NOTIFY_NODE_UP with an empty
cluster_scope takes a node reference and schedules n->work. If the
link flaps down and up while that work is still pending, the next
NODE_UP takes another reference, but schedule_work() returns false
and the extra reference is never dropped. The tipc_node structure
leaks.

Verified by flapping the bearer while the work is pending: one
reference is leaked per repeated NODE_UP, while the work is put only
once when it finally runs.

Drop the reference when the work was already queued.

Reported-by: Xiang Mei <xmei5@asu.edu>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
---
 net/tipc/node.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/tipc/node.c b/net/tipc/node.c
index b545a47d6ccb..428c4eacd02f 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -447,7 +447,8 @@ static void tipc_node_write_unlock(struct tipc_node *n)
 		/* Defer bulk distribution to work queue */
 		if (rc > 0) {
 			tipc_node_get(n);
-			schedule_work(&n->work);
+			if (!schedule_work(&n->work))
+				tipc_node_put(n);
 		} else if (rc < 0) {
 			/* Bring the link down to start over bulk distribution
 			 * when the link is up again.
-- 
2.43.0