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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: 9012de5089 ("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>
hifive-unleashed-5.1
Jon Maloy 2018-07-18 19:50:06 +02:00 committed by David S. Miller
parent f91a0effca
commit 40999f11ce
1 changed files with 4 additions and 0 deletions
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4
net/tipc/node.c
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@ -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);