MDEV-30516 : Assertion `wsrep_cluster_address[0]' failed in void wsre…

mysql-test/suite/wsrep/r/wsrep_cluster_address_update.result

@@ -0,0 +1,28 @@
+#
+# Set sync point and change cluster address, it will block
+#
+connect con1, localhost, root;
+SET DEBUG_SYNC = "wsrep_cluster_address_update SIGNAL update_reached WAIT_FOR continue";
+SET GLOBAL wsrep_cluster_address='gcomm://';;
+#
+# Wait until sync point is reached
+#
+connect con_ctrl, localhost, root;
+SET DEBUG_SYNC = "now WAIT_FOR update_reached";
+#
+# set !wsrep_cluster_address[0], that failed earlier
+#
+connect con2, localhost, root;
+SET GLOBAL wsrep_cluster_address='';;
+connection con_ctrl;
+#
+# Signal cluster address update to continue
+#
+SET DEBUG_SYNC = "now SIGNAL continue";
+disconnect con1;
+disconnect con2;
+connect con1, localhost, root;
+# restart
+disconnect con_ctrl;
+call mtr.add_suppression(".*mariadbd got signal.*");
+call mtr.add_suppression("Attempting backtrace. Include this in the bug report.");

mysql-test/suite/wsrep/t/wsrep_cluster_address_update.cnf

@@ -0,0 +1,13 @@
+# Use default setting for mysqld processes
+!include include/default_mysqld.cnf
+
+[mysqld.1]
+wsrep-on=ON
+binlog-format=ROW
+innodb-flush-log-at-trx-commit=1
+wsrep-cluster-address=gcomm://
+[email protected]_PROVIDER
+innodb-autoinc-lock-mode=2
+#[email protected]
+#[email protected]
+#[email protected]

mysql-test/suite/wsrep/t/wsrep_cluster_address_update.test

@@ -0,0 +1,41 @@
+--source include/have_wsrep.inc
+--source include/have_innodb.inc
+--source include/have_wsrep_provider.inc
+--source include/have_debug_sync.inc
+
+--echo #
+--echo # Set sync point and change cluster address, it will block
+--echo #
+--connect con1, localhost, root
+SET DEBUG_SYNC = "wsrep_cluster_address_update SIGNAL update_reached WAIT_FOR continue";
+--send SET GLOBAL wsrep_cluster_address='gcomm://';
+
+--echo #
+--echo # Wait until sync point is reached
+--echo #
+--connect con_ctrl, localhost, root
+SET DEBUG_SYNC = "now WAIT_FOR update_reached";
+
+--echo #
+--echo # set !wsrep_cluster_address[0], that failed earlier
+--echo #
+--connect con2, localhost, root
+--send SET GLOBAL wsrep_cluster_address='';
+
+--connection con_ctrl
+--echo #
+--echo # Signal cluster address update to continue
+--echo #
+--error 0,2013
+SET DEBUG_SYNC = "now SIGNAL continue";
+sleep 2;
+
+--disconnect con1
+--disconnect con2
+
+--connect con1, localhost, root
+--source include/restart_mysqld.inc
+
+--disconnect con_ctrl
+call mtr.add_suppression(".*mariadbd got signal.*");
+call mtr.add_suppression("Attempting backtrace. Include this in the bug report.");

sql/wsrep_mysqld.cc

@@ -986,7 +986,7 @@ void wsrep_init_startup (bool sst_first)
   */
   if (!wsrep_start_replication(wsrep_cluster_address)) unireg_abort(1);
 
-  wsrep_create_rollbacker();
+  wsrep_create_rollbacker(wsrep_cluster_address);
   wsrep_create_appliers(1);
 
   Wsrep_server_state& server_state= Wsrep_server_state::instance();

sql/wsrep_thd.cc

@@ -1,4 +1,4 @@
-/* Copyright (C) 2013-2023 Codership Oy <[email protected]>
+/* Copyright (C) 2013-2025 Codership Oy <[email protected]>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -278,9 +278,9 @@ static void wsrep_rollback_process(THD *rollbacker,
   DBUG_VOID_RETURN;
 }
 
-void wsrep_create_rollbacker()
+void wsrep_create_rollbacker(const char* cluster_address)
 {
-  DBUG_ASSERT(wsrep_cluster_address[0]);
+  DBUG_ASSERT(cluster_address[0]);
   Wsrep_thd_args* args(new Wsrep_thd_args(wsrep_rollback_process,
                                           WSREP_ROLLBACKER_THREAD,
                                           pthread_self()));

sql/wsrep_thd.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2013-2023 Codership Oy <[email protected]>
+/* Copyright (C) 2013-2025 Codership Oy <[email protected]>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -85,7 +85,7 @@ class Wsrep_thd_queue
 int wsrep_show_bf_aborts (THD *thd, SHOW_VAR *var, void *, system_status_var *,
                           enum enum_var_type scope);
 bool wsrep_create_appliers(long threads, bool mutex_protected=false);
-void wsrep_create_rollbacker();
+void wsrep_create_rollbacker(const char*);
 
 bool wsrep_bf_abort(THD* bf_thd, THD* victim_thd);
 /*

sql/wsrep_var.cc

@@ -1,4 +1,4 @@
-/* Copyright 2008-2023 Codership Oy <http://www.codership.com>
+/* Copyright 2008-2025 Codership Oy <http://www.codership.com>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -657,15 +657,24 @@ bool wsrep_cluster_address_update (sys_var *self, THD* thd, enum_var_type type)
   char *tmp= my_strdup(PSI_INSTRUMENT_ME, wsrep_cluster_address, MYF(MY_WME));
   WSREP_DEBUG("wsrep_cluster_address_update: %s", wsrep_cluster_address);
   mysql_mutex_unlock(&LOCK_global_system_variables);
-
+  /* Here, wsrep_cluster_address can be changed */
+  DEBUG_SYNC(thd, "wsrep_cluster_address_update");
   mysql_mutex_lock(&LOCK_wsrep_cluster_config);
   wsrep_stop_replication(thd);
+  /*
+     Note that we can't lock LOCK_global_system_variables yet
+     because in below LOCK_wsrep_slave_threads is aquired
+     and correct mutexing order is LOCK_wsrep_slave_threads
+     and then LOCK_global_system_variables.
 
+     tmp passed below because wsrep_cluster_address could have
+     been changed meanwhile.
+  */
   if (*tmp && wsrep_start_replication(tmp))
   {
-    wsrep_create_rollbacker();
-    WSREP_DEBUG("Cluster address update creating %ld applier threads running %lu",
-                wsrep_slave_threads, wsrep_running_applier_threads);
+    wsrep_create_rollbacker(tmp);
+    WSREP_INFO("Cluster address update to %s creating %ld applier threads running %lu",
+                tmp, wsrep_slave_threads, wsrep_running_applier_threads);
     wsrep_create_appliers(wsrep_slave_threads);
   }
   mysql_mutex_unlock(&LOCK_wsrep_cluster_config);