refs codership/mysql-wsrep#233

- added dbug sync points for further mtr test for this issue

sql/mdl.cc

@@ -24,6 +24,7 @@
 #include <mysql/psi/mysql_stage.h>
 
 #ifdef WITH_WSREP
+#include "debug_sync.h"
 #include "wsrep_mysqld.h"
 #include "wsrep_thd.h"
 extern "C" my_thread_id wsrep_thd_thread_id(THD *thd);
@@ -1445,6 +1446,15 @@ MDL_wait::timed_wait(MDL_context_owner *owner, struct timespec *abs_timeout,
          wait_result != ETIMEDOUT && wait_result != ETIME)
   {
 #ifdef WITH_WSREP
+    // Allow tests to block the applier thread using the DBUG facilities
+    DBUG_EXECUTE_IF("sync.wsrep_before_mdl_wait",
+                 {
+                   const char act[]=
+                     "now "
+                     "wait_for signal.wsrep_before_mdl_wait";
+                   DBUG_ASSERT(!debug_sync_set_action((owner->get_thd()),
+                                                      STRING_WITH_LEN(act)));
+                 };);
     if (wsrep_thd_is_BF(owner->get_thd(), true))
     {
       wait_result= mysql_cond_wait(&m_COND_wait_status, &m_LOCK_wait_status);

storage/innobase/handler/ha_innodb.cc

@@ -17357,6 +17357,15 @@ wsrep_innobase_kill_one_trx(
 		  (thd && wsrep_thd_query(thd)) ? wsrep_thd_query(thd) : "void");
 
 	wsrep_thd_LOCK(thd);
+        DBUG_EXECUTE_IF("sync.wsrep_after_BF_victim_lock",
+                 {
+                   const char act[]=
+                     "now "
+                     "wait_for signal.wsrep_after_BF_victim_lock";
+                   DBUG_ASSERT(!debug_sync_set_action(bf_thd,
+                                                      STRING_WITH_LEN(act)));
+                 };);
+
 
 	if (wsrep_thd_query_state(thd) == QUERY_EXITING) {
 		WSREP_DEBUG("kill trx EXITING for %lu", victim_trx->id);