[IPSEC]: Do not hold state lock while checking size.

This can elicit ICMP message output and thus result in a
deadlock.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/xfrm4_output.c

@@ -103,17 +103,17 @@ int xfrm4_output(struct sk_buff *skb)
 			goto error_nolock;
 	}
 
-	spin_lock_bh(&x->lock);
-	err = xfrm_state_check(x, skb);
-	if (err)
-		goto error;
-
 	if (x->props.mode) {
 		err = xfrm4_tunnel_check_size(skb);
 		if (err)
-			goto error;
+			goto error_nolock;
 	}
 
+	spin_lock_bh(&x->lock);
+	err = xfrm_state_check(x, skb);
+	if (err)
+		goto error;
+
 	xfrm4_encap(skb);
 
 	err = x->type->output(x, skb);

net/ipv6/xfrm6_output.c

@@ -103,17 +103,17 @@ int xfrm6_output(struct sk_buff *skb)
 			goto error_nolock;
 	}
 
-	spin_lock_bh(&x->lock);
-	err = xfrm_state_check(x, skb);
-	if (err)
-		goto error;
-
 	if (x->props.mode) {
 		err = xfrm6_tunnel_check_size(skb);
 		if (err)
-			goto error;
+			goto error_nolock;
 	}
 
+	spin_lock_bh(&x->lock);
+	err = xfrm_state_check(x, skb);
+	if (err)
+		goto error;
+
 	xfrm6_encap(skb);
 
 	err = x->type->output(x, skb);