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authorEric Dumazet <edumazet@google.com>2012-06-08 06:25:00 +0000
committerDavid S. Miller <davem@davemloft.net>2012-06-08 14:30:51 -0700
commit4399a4df98a63e30fd16e9d0cecc46ea92269e8f (patch)
tree6068b48be8fe07b2501a849b152436c42106650d /net/l2tp
parent6a2b28ef036ab5c66fdc606fe97d9e5cb34ea409 (diff)
downloadlinux-4399a4df98a63e30fd16e9d0cecc46ea92269e8f.tar.gz
l2tp: fix a race in l2tp_ip_sendmsg()
Commit 081b1b1bb27f (l2tp: fix l2tp_ip_sendmsg() route handling) added a race, in case IP route cache is disabled. In this case, we should not do the dst_release(&rt->dst), since it'll free the dst immediately, instead of waiting a RCU grace period. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: James Chapman <jchapman@katalix.com> Cc: Denys Fedoryshchenko <denys@visp.net.lb> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/l2tp')
-rw-r--r--net/l2tp/l2tp_ip.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
index 70614e7affa..61d8b75d268 100644
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -464,10 +464,12 @@ static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
sk->sk_bound_dev_if);
if (IS_ERR(rt))
goto no_route;
- if (connected)
+ if (connected) {
sk_setup_caps(sk, &rt->dst);
- else
- dst_release(&rt->dst); /* safe since we hold rcu_read_lock */
+ } else {
+ skb_dst_set(skb, &rt->dst);
+ goto xmit;
+ }
}
/* We dont need to clone dst here, it is guaranteed to not disappear.
@@ -475,6 +477,7 @@ static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
*/
skb_dst_set_noref(skb, &rt->dst);
+xmit:
/* Queue the packet to IP for output */
rc = ip_queue_xmit(skb, &inet->cork.fl);
rcu_read_unlock();