dhcp: calls to vnet_feature_enable_disable needs to be protected

dhcp is makeing calls to vnet_feature_enable_disable without barrier sync
protection. This can cause data contention with the worker threads. Wrap
all calls to vnet_feature_enable_disable with barrier sync and barrier
release.

Type: fix

Signed-off-by: Steven Luong <sluong@cisco.com>
Change-Id: I74545b074599273429f47e3e726551156bc11bbc

diff --git a/src/plugins/dhcp/client.c b/src/plugins/dhcp/client.c
index e15b6cb..e79cb69 100644 (file)
--- a/src/plugins/dhcp/client.c
+++ b/src/plugins/dhcp/client.c
@@ -246,6 +246,7 @@ dhcp_client_addr_callback (u32 * cindex)
 static void
 dhcp_client_reset (dhcp_client_main_t * dcm, dhcp_client_t * c)
 {
+  vlib_worker_thread_barrier_sync (dcm->vlib_main);
   if (c->client_detect_feature_enabled == 1)
     {
       vnet_feature_enable_disable ("ip4-unicast",
@@ -253,8 +254,9 @@ dhcp_client_reset (dhcp_client_main_t * dcm, dhcp_client_t * c)
                                   c->sw_if_index, 0, 0, 0);
       c->client_detect_feature_enabled = 0;
     }
-
   dhcp_client_release_address (dcm, c);
+  vlib_worker_thread_barrier_release (dcm->vlib_main);
+
   clib_memset (&c->learned, 0, sizeof (c->installed));
   c->state = DHCP_DISCOVER;
   c->next_transmit = vlib_time_now (dcm->vlib_main);
@@ -704,9 +706,11 @@ dhcp_discover_state (dhcp_client_main_t * dcm, dhcp_client_t * c, f64 now)
    */
   if (c->client_detect_feature_enabled == 0)
     {
+      vlib_worker_thread_barrier_sync (dcm->vlib_main);
       vnet_feature_enable_disable ("ip4-unicast",
                                   "ip4-dhcp-client-detect",
                                   c->sw_if_index, 1 /* enable */ , 0, 0);
+      vlib_worker_thread_barrier_release (dcm->vlib_main);
       c->client_detect_feature_enabled = 1;
     }
 
@@ -754,9 +758,11 @@ dhcp_bound_state (dhcp_client_main_t * dcm, dhcp_client_t * c, f64 now)
    */
   if (c->client_detect_feature_enabled == 0)
     {
+      vlib_worker_thread_barrier_sync (dcm->vlib_main);
       vnet_feature_enable_disable ("ip4-unicast",
                                   "ip4-dhcp-client-detect",
                                   c->sw_if_index, 1 /* enable */ , 0, 0);
+      vlib_worker_thread_barrier_release (dcm->vlib_main);
       c->client_detect_feature_enabled = 1;
     }