memif: contention between memif_disconnect and memif RX/TX threads

memif_disconect may be called without barrier sync. It removes stuff in mq
without protection which may cause troubles for memif RX/TX worker threads.

The fix is to protect mq removal in memif_disconnect.

Type: fix

Change-Id: I368c466d1f13df98980dfa87e8442fbcd822a428
Signed-off-by: Steven Luong <sluong@cisco.com>

diff --git a/src/plugins/memif/memif.c b/src/plugins/memif/memif.c
index 37028d8..22f3e3d 100644 (file)
--- a/src/plugins/memif/memif.c
+++ b/src/plugins/memif/memif.c
@@ -100,6 +100,8 @@ memif_disconnect (memif_if_t * mif, clib_error_t * err)
   memif_region_t *mr;
   memif_queue_t *mq;
   int i;
+  vlib_main_t *vm = vlib_get_main ();
+  int with_barrier = 0;
 
   if (mif == 0)
     return;
@@ -141,6 +143,12 @@ memif_disconnect (memif_if_t * mif, clib_error_t * err)
       clib_mem_free (mif->sock);
     }
 
+  if (vlib_worker_thread_barrier_held () == 0)
+    {
+      with_barrier = 1;
+      vlib_worker_thread_barrier_sync (vm);
+    }
+
   /* *INDENT-OFF* */
   vec_foreach_index (i, mif->rx_queues)
     {
@@ -198,6 +206,9 @@ memif_disconnect (memif_if_t * mif, clib_error_t * err)
   vec_free (mif->remote_name);
   vec_free (mif->remote_if_name);
   clib_fifo_free (mif->msg_queue);
+
+  if (with_barrier)
+    vlib_worker_thread_barrier_release (vm);
 }
 
 static clib_error_t *