Merge mysql-trunk-innodb from bk-internal locally

storage/innobase/srv/srv0srv.c

@@ -3082,9 +3082,13 @@ srv_purge_thread(
 		srv_sync_log_buffer_in_background();
 	}
 
+	mutex_enter(&kernel_mutex);
+
 	/* Decrement the active count. */
 	srv_suspend_thread();
 
+	mutex_exit(&kernel_mutex);
+
 	/* Free the thread local memory. */
 	thr_local_free(os_thread_get_curr_id());