udp: fix buffer trace

Type: fix

Signed-off-by: Andreas Schultz <andreas.schultz@travelping.com>
Change-Id: I774ca50582281cb3cc5e43417e74d178bf4909bd
diff --git a/src/vnet/udp/udp_input.c b/src/vnet/udp/udp_input.c
index 95595c3..296a874 100644
--- a/src/vnet/udp/udp_input.c
+++ b/src/vnet/udp/udp_input.c
@@ -317,14 +317,13 @@
 	}
 
     done:
+      if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
+	udp_trace_buffer (vm, node, b[0], s0, error0);
 
       b += 1;
       n_left_from -= 1;
 
       udp_inc_err_counter (err_counters, error0, 1);
-
-      if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
-	udp_trace_buffer (vm, node, b[0], s0, error0);
     }
 
   vlib_buffer_free (vm, first_buffer, frame->n_vectors);