dpif-netdev: Clear flow batches before execute.

When executing actions, it's possible a recirculation will occur
causing dp_netdev_input() to be called multiple times.  If the batch
pointers embedded in dp_netdev_flow aren't cleared, it's possible
packets after the recirculation will be reinserted into a batch
associated with the original lookup.  This could be very bad.

This patch fixes the problem by zeroing out flow batch pointers before
calling packet_batch_execute().  This probably has a slightly negative
performance impact, though I haven't tried it.

Signed-off-by: Ethan Jackson <ethan@nicira.com>
Acked-by: Daniele Di Proietto <diproiettod@vmware.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index b4a42eb11..ff583e7b1 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -3066,7 +3066,6 @@ packet_batch_execute(struct packet_batch *batch,
     struct dp_netdev_actions *actions;
     struct dp_netdev_flow *flow = batch->flow;
 
-    flow->batch = NULL;
     dp_netdev_flow_used(flow, batch->packet_count, batch->byte_count,
                         batch->tcp_flags, now);
 
@@ -3299,6 +3298,10 @@ dp_netdev_input(struct dp_netdev_pmd_thread *pmd,
     }
 
     for (i = 0; i < n_batches; i++) {
+        batches[i].flow->batch = NULL;
+    }
+
+    for (i = 0; i < n_batches; i++) {
         packet_batch_execute(&batches[i], pmd, now);
     }
 }