Commit 40999f11 authored Jul 18, 2018 by Jon Maloy Committed by David S. Miller Jul 20, 2018

tipc: make link capability update thread safe

The commit referred to below introduced an update of the link
capabilities field that is not safe. Given the recently added
feature to remove idle node and link items after 5 minutes, there
is a small risk that the update will happen at the very moment the
targeted link is being removed. To avoid this we have to perform
the update inside the node item's write lock protection.

Fixes: 9012de50 ("tipc: add sequence number check for link STATE messages")
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent f91a0eff

net/tipc/node.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -370,13 +370,17 @@ static struct tipc_node tipc_node_create(struct net net, u32 addr,
		spin_lock_bh(&tn->node_list_lock);
		n = tipc_node_find(net, addr);
		if (n) {
		if (n->capabilities == capabilities)
		goto exit;
		/* Same node may come back with new capabilities */
		write_lock_bh(&n->lock);
		n->capabilities = capabilities;
		for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
		l = n->links[bearer_id].link;
		if (l)
		tipc_link_update_caps(l, capabilities);
		}
		write_unlock_bh(&n->lock);
		goto exit;
		}
		n = kzalloc(sizeof(*n), GFP_ATOMIC);

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