MDEV-23101 : SIGSEGV in lock_rec_unlock() when Galera is enabled

Remove incorrect BF (brute force) handling from lock_rec_has_to_wait_in_queue and move condition to correct callers. Add a function to report BF lock waits and assert if incorrect BF-BF lock wait happens. wsrep_report_bf_lock_wait	Add a new function to report BF lock wait. wsrep_assert_no_bf_bf_wait	Add a new function to check do we have a	BF-BF wait and if we have report this case	and assert as it is a bug. lock_rec_has_to_wait	Use new wsrep_assert_bf_wait to check BF-BF wait. lock_rec_create_low lock_table_create	Use new function to report BF lock waits. lock_rec_insert_by_trx_age lock_grant_and_move_on_page lock_grant_and_move_on_rec	Assert that trx is not Galera as VATS is not compatible	with Galera. lock_rec_add_to_queue	If there is conflicting lock in a queue make sure that	transaction is BF. lock_rec_has_to_wait_in_queue	Remove incorrect BF handling. If there is conflicting	locks in a queue all transactions must wait. lock_rec_dequeue_from_page lock_rec_unlock	If there is conflicting lock make sure it is not	BF-BF case. lock_rec_queue_validate	Add Galera record locking rules comment and use	new function to report BF lock waits. All attempts to reproduce the original assertion have been failed. Therefore, there is no test case on this commit.

Author: janlindstrom

include/mysql/service_wsrep.h

@@ -115,6 +115,8 @@ extern struct wsrep_service_st {
  void (*wsrep_unlock_rollback_func)();
  void (*wsrep_set_data_home_dir_func)(const char *data_dir);
  my_bool (*wsrep_thd_is_applier_func)(MYSQL_THD);
+ void (*wsrep_report_bf_lock_wait_func)(MYSQL_THD thd,
+ unsigned long long trx_id);
 } *wsrep_service;
 
 #ifdef MYSQL_DYNAMIC_PLUGIN
@@ -161,6 +163,7 @@ extern struct wsrep_service_st {
 #define wsrep_unlock_rollback() wsrep_service->wsrep_unlock_rollback_func()
 #define wsrep_set_data_home_dir(A) wsrep_service->wsrep_set_data_home_dir_func(A)
 #define wsrep_thd_is_applier(T) wsrep_service->wsrep_thd_is_applier_func(T)
+#define wsrep_report_bf_lock_wait(T,I) wsrep_service->wsrep_report_bf_lock_wait_func(T,I)
 
 #define wsrep_debug get_wsrep_debug()
 #define wsrep_log_conflicts get_wsrep_log_conflicts()
@@ -223,6 +226,8 @@ bool wsrep_thd_ignore_table(THD *thd);
 void wsrep_unlock_rollback();
 void wsrep_set_data_home_dir(const char *data_dir);
 my_bool wsrep_thd_is_applier(MYSQL_THD thd);
+void wsrep_report_bf_lock_wait(THD *thd,
+ unsigned long long trx_id);
 #endif
 
 #ifdef __cplusplus

sql/sql_plugin_services.ic

@@ -184,7 +184,8 @@ static struct wsrep_service_st wsrep_handler = {
  wsrep_trx_order_before,
  wsrep_unlock_rollback,
  wsrep_set_data_home_dir,
- wsrep_thd_is_applier
+ wsrep_thd_is_applier,
+ wsrep_report_bf_lock_wait
 };
 
 static struct thd_specifics_service_st thd_specifics_handler=

sql/wsrep_dummy.cc

@@ -1,4 +1,4 @@
-/* Copyright (C) 2014 SkySQL Ab.
+/* Copyright (C) 2014, 2020, MariaDB
 
  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
@@ -154,3 +154,7 @@ void wsrep_log(void (*)(const char *, ...), const char *, ...)
 
 my_bool wsrep_thd_is_applier(MYSQL_THD thd)
 { return false; }
+
+void wsrep_report_bf_lock_wait(MYSQL_THD thd,
+ unsigned long long id)
+{}

sql/wsrep_thd.cc

@@ -876,3 +876,23 @@ bool wsrep_is_load_multi_commit(THD *thd)
 {
  return thd->wsrep_split_flag;
 }
+
+void wsrep_report_bf_lock_wait(THD *thd,
+ unsigned long long trx_id)
+{
+ if (thd)
+ {
+ WSREP_ERROR("Thread %s trx_id: %llu thread: %ld "
+ "seqno: %lld query_state: %s conf_state: %s exec_mode: %s "
+ "applier: %d query: %s",
+ wsrep_thd_is_BF(thd, false) ? "BF" : "normal",
+ trx_id,
+ thd_get_thread_id(thd),
+ wsrep_thd_trx_seqno(thd),
+ wsrep_thd_query_state_str(thd),
+ wsrep_thd_conflict_state_str(thd),
+ wsrep_thd_exec_mode_str(thd),
+ thd->wsrep_applier,
+ wsrep_thd_query(thd));
+ }
+}

sql/wsrep_thd.h

@@ -45,6 +45,9 @@ extern "C" my_bool wsrep_thd_is_BF_or_commit(void *thd_ptr, my_bool sync);
 extern "C" my_bool wsrep_thd_is_local(void *thd_ptr, my_bool sync);
 extern "C" int wsrep_thd_in_locking_session(void *thd_ptr);
 
+extern void wsrep_report_bf_lock_wait(THD *thd,
+ unsigned long long trx_id);
+
 #else /* WITH_WSREP */
 
 #define wsrep_thd_is_BF(T, S) (0)