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net: fix rcu use in ip_route_output_slow 

__in_dev_get_rtnl(dev_out) is called while RTNL is not held, thus
triggers a lockdep fault.

At this point, we only perform a raw test of dev_out->ip_ptr being NULL,
we dont need to make sure ip_ptr cant changed right after.

We can use rcu_dereference_raw() for this.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2010-09-23 21:46:03 +00:00 committed by David S. Miller
parent 1b4bf461f0
commit 83180af0b0
1 changed files with 1 additions and 1 deletions
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2
net/ipv4/route.c
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@ -2579,7 +2579,7 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
goto out;
/* RACE: Check return value of inet_select_addr instead. */
if (__in_dev_get_rtnl(dev_out) == NULL) {
if (rcu_dereference_raw(dev_out->ip_ptr) == NULL) {
dev_put(dev_out);
goto out; /* Wrong error code */
}