vlib: avoid retrieving freed file in epoll

Type:fix

Change-Id: Id7f4f6e2a2f844085f511a33aa1db3968f5d97bb
Signed-off-by: Florin Coras <fcoras@cisco.com>

diff --git a/src/vlib/unix/input.c b/src/vlib/unix/input.c
index 43bb206..98cb133 100644 (file)
--- a/src/vlib/unix/input.c
+++ b/src/vlib/unix/input.c
@@ -272,17 +272,18 @@ linux_epoll_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
   for (e = em->epoll_events; e < em->epoll_events + n_fds_ready; e++)
     {
       u32 i = e->data.u32;
-      clib_file_t *f = pool_elt_at_index (fm->file_pool, i);
+      clib_file_t *f;
       clib_error_t *errors[4];
       int n_errors = 0;
 
+      /*
+       * Under rare scenarios, epoll may still post us events for the
+       * deleted file descriptor. We just deal with it and throw away the
+       * events for the corresponding file descriptor.
+       */
+      f = fm->file_pool + i;
       if (PREDICT_FALSE (pool_is_free (fm->file_pool, f)))
        {
-         /*
-          * Under rare scenerop, epoll may still post us events for the
-          * deleted file descriptor. We just deal with it and throw away the
-          * events for the corresponding file descriptor.
-          */
          if (e->events & EPOLLIN)
            {
              errors[n_errors] =