fib: refresh adj pointer after fib_walk_sync due to possible realloc

[vpp.git] / src / vnet / ethernet / arp.c

diff --git a/src/vnet/ethernet/arp.c b/src/vnet/ethernet/arp.c
index a42cfda..65de055 100644 (file)
--- a/src/vnet/ethernet/arp.c
+++ b/src/vnet/ethernet/arp.c
@@ -563,6 +563,13 @@ arp_update_adjacency (vnet_main_t * vnm, u32 sw_if_index, u32 ai)
           * wouldn't be bad either, but that's more code than i'm prepared to
           * write at this time for relatively little reward.
           */
+         /*
+          * adj_nbr_update_rewrite may actually call fib_walk_sync.
+          * fib_walk_sync may allocate a new adjacency and potentially cause
+          * a realloc for adj_pool. When that happens, adj pointer is no
+          * longer valid here. We refresh adj pointer accordingly.
+          */
+         adj = adj_get (ai);
          arp_nbr_probe (adj);
        }
       break;
@@ -574,6 +581,13 @@ arp_update_adjacency (vnet_main_t * vnm, u32 sw_if_index, u32 ai)
                               sw_if_index,
                               VNET_LINK_IP4,
                               VNET_REWRITE_FOR_SW_INTERFACE_ADDRESS_BROADCAST));
+      /*
+       * Caution: adj_nbr_update_rewrite may actually call fib_walk_sync.
+       * fib_walk_sync may allocate a new adjacency and potentially cause a
+       * realloc for adj_pool. When that happens, adj pointer is no longer
+       * valid here. Please refresh adj pointer accordingly if it is still
+       * needed after the aformentioned call.
+       */
       break;
     case IP_LOOKUP_NEXT_MCAST:
       {