Cleanups and fixes

- Added missing delete thd in bootstrap()
- Delete wrong 'delete thd' in start_wsrep_THD()
- Added missing 'delete thd' in case of SCHEDULER_ONE_THREAD_PER_CONNECTION
- Delete wrong dec_thread_running() in destroy_thd() as it caused thread_running
  to be wrong.
- Moved reset_killed() to a normal function to make it easier to debug
- Added check of mutex in wsrep_aborting_thd... functions

sql/mysqld.cc

@@ -6396,6 +6396,7 @@ static void bootstrap(MYSQL_FILE *file)
     sql_print_warning("Can't create thread to handle bootstrap (errno= %d)",
                       error);
     bootstrap_error=-1;
+    delete thd;
     DBUG_VOID_RETURN;
   }
   /* Wait for thread to die */

sql/sql_class.cc

@@ -2067,6 +2067,23 @@ int THD::killed_errno()
 }
 
 
+void THD::reset_killed()
+{
+  /*
+    Resetting killed has to be done under a mutex to ensure
+    its not done during an awake() call.
+  */
+  DBUG_ENTER("reset_killed");
+  if (killed != NOT_KILLED)
+  {
+    mysql_mutex_lock(&LOCK_thd_kill);
+    killed= NOT_KILLED;
+    killed_err= 0;
+    mysql_mutex_unlock(&LOCK_thd_kill);
+  }
+  DBUG_VOID_RETURN;
+}
+
 /*
   Remember the location of thread info, the structure needed for
   the structure for the net buffer
@@ -4630,7 +4647,6 @@ void destroy_thd(MYSQL_THD thd)
   thd->add_status_to_global();
   unlink_not_visible_thd(thd);
   delete thd;
-  dec_thread_running();
 }
 
 void reset_thd(MYSQL_THD thd)

sql/sql_class.h

@@ -3737,20 +3737,7 @@ public:
     }
   }
   int killed_errno();
-  inline void reset_killed()
-  {
-    /*
-      Resetting killed has to be done under a mutex to ensure
-      its not done during an awake() call.
-    */
-    if (killed != NOT_KILLED)
-    {
-      mysql_mutex_lock(&LOCK_thd_kill);
-      killed= NOT_KILLED;
-      killed_err= 0;
-      mysql_mutex_unlock(&LOCK_thd_kill);
-    }
-  }
+  void reset_killed();
   inline void reset_kill_query()
   {
     if (killed < KILL_CONNECTION)

sql/wsrep_mysqld.cc

@@ -1935,7 +1935,6 @@ pthread_handler_t start_wsrep_THD(void *arg)
     close_connection(thd, ER_OUT_OF_RESOURCES);
     statistic_increment(aborted_connects,&LOCK_status);
     MYSQL_CALLBACK(thread_scheduler, end_thread, (thd, 0));
-
     goto error;
   }
 
@@ -1958,7 +1957,6 @@ pthread_handler_t start_wsrep_THD(void *arg)
     close_connection(thd, ER_OUT_OF_RESOURCES);
     statistic_increment(aborted_connects,&LOCK_status);
     MYSQL_CALLBACK(thread_scheduler, end_thread, (thd, 0));
-    delete thd;
     goto error;
   }
 
@@ -2002,13 +2000,8 @@ pthread_handler_t start_wsrep_THD(void *arg)
     // at server shutdown
   }
 
-  if (thread_handling > SCHEDULER_ONE_THREAD_PER_CONNECTION)
-  {
-    mysql_mutex_lock(&LOCK_thread_count);
-    thd->unlink();
-    mysql_mutex_unlock(&LOCK_thread_count);
+  unlink_not_visible_thd(thd);
   delete thd;
-  }
   my_thread_end();
   return(NULL);
 
@@ -2733,6 +2726,7 @@ void wsrep_unlock_rollback()
 
 my_bool wsrep_aborting_thd_contains(THD *thd)
 {
+  mysql_mutex_assert_owner(&LOCK_wsrep_rollback);
   wsrep_aborting_thd_t abortees = wsrep_aborting_thd;
   while (abortees)
   {