From db61ecc3352d72513c1b07805bd6f760e30c001b Mon Sep 17 00:00:00 2001 From: "Tommy S. Christensen" Date: Thu, 19 May 2005 12:46:59 -0700 Subject: [PATCH] [NETLINK]: Fix race with recvmsg(). This bug causes: assertion (!atomic_read(&sk->sk_rmem_alloc)) failed at net/netlink/af_netlink.c (122) What's happening is that: 1) The skb is sent to socket 1. 2) Someone does a recvmsg on socket 1 and drops the ref on the skb. Note that the rmalloc is not returned at this point since the skb is still referenced. 3) The same skb is now sent to socket 2. This version of the fix resurrects the skb_orphan call that was moved out, last time we had 'shared-skb troubles'. It is practically a no-op in the common case, but still prevents the possible race with recvmsg. Signed-off-by: Tommy S. Christensen Acked-by: Herbert Xu Signed-off-by: David S. Miller --- net/netlink/af_netlink.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 733bf52cef..b40c9a9769 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -697,6 +697,7 @@ static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && !test_bit(0, &nlk->state)) { + skb_orphan(skb); skb_set_owner_r(skb, sk); skb_queue_tail(&sk->sk_receive_queue, skb); sk->sk_data_ready(sk, skb->len); -- 2.39.5