Merge 10.4 into 10.5

extra/mariabackup/innobackupex.cc

@@ -112,6 +112,8 @@ bool ibx_partial_backup = false;
 char *ibx_position_arg = NULL;
 char *ibx_backup_directory = NULL;
 
+extern bool xb_opt_destroy_password;
+
 /* copy of proxied xtrabackup options */
 my_bool ibx_xb_close_files;
 const char *ibx_xtrabackup_compress_alg;
@@ -770,18 +772,7 @@ ibx_get_one_option(const struct my_option *opt,
 		xtrabackup_compress = TRUE;
 		break;
 	case 'p':
-		if (argument)
-		{
-		        char *start = argument;
-			my_free(opt_ibx_password);
-			opt_ibx_password= my_strdup(PSI_NOT_INSTRUMENTED,
-                                                    argument, MYF(MY_FAE));
-			/*  Destroy argument */
-			while (*argument)
-				*argument++= 'x';
-			if (*start)
-				start[1]=0 ;
-		}
+    opt_ibx_password= argument;
 		break;
         }
 	return(0);

include/my_getopt.h

@@ -106,6 +106,7 @@ extern char *autoset_my_option;
 extern my_bool my_getopt_print_errors;
 extern my_bool my_getopt_skip_unknown;
 extern my_bool my_getopt_prefix_matching;
+extern my_bool my_handle_options_init_variables;
 extern my_error_reporter my_getopt_error_reporter;
 extern my_getopt_value my_getopt_get_addr;
 

include/violite.h

@@ -174,6 +174,8 @@ struct st_VioSSLFd
 int sslaccept(struct st_VioSSLFd*, Vio *, long timeout, unsigned long *errptr);
 int sslconnect(struct st_VioSSLFd*, Vio *, long timeout, unsigned long *errptr);
 
+void vio_check_ssl_init();
+
 struct st_VioSSLFd
 *new_VioSSLConnectorFd(const char *key_file, const char *cert_file,
 		       const char *ca_file,  const char *ca_path,

mysql-test/main/mdev_22370.result

+connect  con1,localhost,root,,;
+SET DEBUG_DBUG='+d,mark_busy_mdev_22370';
+FLUSH TABLES WITH READ LOCK;
+connection default;
+# restart

mysql-test/main/mdev_22370.test

+#
+# MDEV-22370 safe_mutex: Trying to lock uninitialized mutex at
+#   /data/src/10.4-bug/sql/rpl_parallel.cc, line 470 upon shutdown during FTWRL
+#
+# Purpose of this test case to test crash while FTWRL and shutdown is in race
+# condition
+# Shutdown can execute first and destroy the mutex making mutex_lock in pool_mark_busy
+# to crash
+
+--source include/have_debug.inc
+--connect (con1,localhost,root,,)
+SET DEBUG_DBUG='+d,mark_busy_mdev_22370';
+--send
+  FLUSH TABLES WITH READ LOCK;
+
+--connection default
+--source include/restart_mysqld.inc

mysql-test/suite/mariabackup/apply-log-only-incr.test

@@ -36,7 +36,7 @@ connection default;
 
 --disable_result_log
 exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf  --backup --ftwrl-wait-timeout=5 --ftwrl-wait-threshold=300 --ftwrl-wait-query-type=all --target-dir=$incremental_dir --incremental-basedir=$basedir ;
-exec $XTRABACKUP --prepare --verbose --apply-log-only --target-dir=$basedir ;
+exec $XTRABACKUP --prepare --verbose --target-dir=$basedir ;
 --enable_result_log
 
 let SEARCH_FILE=$MYSQLTEST_VARDIR/log/current_test;
@@ -44,7 +44,7 @@ let SEARCH_FILE=$MYSQLTEST_VARDIR/log/current_test;
 --source include/search_pattern_in_file.inc
 --echo # expect NOT FOUND
 
-exec $XTRABACKUP --prepare --verbose --apply-log-only --target-dir=$basedir --incremental-dir=$incremental_dir ;
+exec $XTRABACKUP --prepare --verbose --target-dir=$basedir --incremental-dir=$incremental_dir ;
 
 --source include/search_pattern_in_file.inc
 --echo # expect NOT FOUND

mysql-test/suite/mariabackup/apply-log-only.test

@@ -11,7 +11,7 @@ INSERT INTO t VALUES(1);
 exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf  --backup --target-dir=$basedir;
 --enable_result_log
 
-exec $XTRABACKUP --prepare --apply-log-only --target-dir=$basedir ;
+exec $XTRABACKUP --prepare --target-dir=$basedir ;
 
 let SEARCH_FILE=$MYSQLTEST_VARDIR/log/current_test;
 --let SEARCH_PATTERN= Rolled back recovered transaction

mysql-test/suite/mariabackup/binlog.test

@@ -12,7 +12,7 @@ SHOW VARIABLES like 'log_bin';
 exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf  --backup --target-dir=$basedir;
 --enable_result_log
 
-exec $XTRABACKUP --prepare --binlog-info=1 --apply-log-only --target-dir=$basedir ;
+exec $XTRABACKUP --prepare --binlog-info=1 --target-dir=$basedir ;
 
 let SEARCH_FILE=$MYSQLTEST_VARDIR/log/current_test;
 --let SEARCH_PATTERN= Last binlog file .*, position .*

mysql-test/suite/mariabackup/incremental_ddl_before_backup.test

@@ -33,7 +33,7 @@ select count(*) from t7;
 exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf  --backup --target-dir=$incremental_dir --incremental-basedir=$basedir;
 
 --echo # XTRABACKUP PREPARE
-exec $XTRABACKUP --apply-log-only --prepare --target-dir=$basedir;
+exec $XTRABACKUP --prepare --target-dir=$basedir;
 
 --echo # XTRABACKUP INCREMENTAL PREPARE
 exec $XTRABACKUP --prepare --target-dir=$basedir --incremental-dir=$incremental_dir;

mysql-test/suite/mariabackup/incremental_ddl_during_backup.test

@@ -25,7 +25,7 @@ exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf  --backup --target-dir
 --let after_load_tablespaces=
 --disable_result_log
 echo # Prepare full backup, apply incremental one;
-exec $XTRABACKUP --apply-log-only --prepare --target-dir=$basedir;
+exec $XTRABACKUP --prepare --target-dir=$basedir;
 exec $XTRABACKUP --prepare --target-dir=$basedir --incremental-dir=$incremental_dir ;
 
 echo # Restore and check results;

mysql-test/suite/mariabackup/mdev-14447.test

@@ -30,9 +30,9 @@ remove_file $backuplog;
 
 --disable_result_log
 echo # Prepare full backup, apply incremental one;
-exec $XTRABACKUP --prepare --verbose --apply-log-only --target-dir=$basedir;
+exec $XTRABACKUP --prepare --verbose --target-dir=$basedir;
 
-exec $XTRABACKUP --prepare --verbose --apply-log-only --target-dir=$basedir --incremental-dir=$incremental_dir ;
+exec $XTRABACKUP --prepare --verbose --target-dir=$basedir --incremental-dir=$incremental_dir ;
 
 echo # Restore and check results;
 let $targetdir=$basedir;

mysql-test/suite/mariabackup/options_check.result

+# Check for unknown options in command-line
+# Check for unknown options in "mariabackup" group
+# Check for unknown options in "xtrabackup" group
+# Check for unknown options in "mariadb-backup" group
+# Check for options overwriting
+# Check if uknown options that follow --mysqld-args are ingored
+# Check if [mariadb-client] group is not loaded (MDEV-22894)

mysql-test/suite/mariabackup/options_check.test

+--let $targetdir=$MYSQLTEST_VARDIR/tmp/backup
+--let $custom_cnf=$MYSQLTEST_VARDIR/tmp/custom_my.cnf
+
+--echo # Check for unknown options in command-line
+--disable_result_log
+--error 7
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --unknown-option=xxx --target-dir=$targetdir;
+--error 2
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --unknown-option --target-dir=$targetdir;
+--enable_result_log
+
+--echo # Check for unknown options in "mariabackup" group
+--write_file $custom_cnf
+[mariabackup]
+unknown-option=XXX
+EOF
+--error 7
+exec $XTRABACKUP --defaults-file=$custom_cnf --backup --target-dir=$targetdir;
+--remove_file $custom_cnf
+
+--echo # Check for unknown options in "xtrabackup" group
+--write_file $custom_cnf
+[xtrabackup]
+unknown-option=XXX
+EOF
+--error 7
+exec $XTRABACKUP --defaults-file=$custom_cnf --backup --target-dir=$targetdir;
+--remove_file $custom_cnf
+
+--echo # Check for unknown options in "mariadb-backup" group
+--write_file $custom_cnf
+[mariadb-backup]
+unknown-option=XXX
+EOF
+--error 7
+exec $XTRABACKUP --defaults-file=$custom_cnf --backup --target-dir=$targetdir;
+--remove_file $custom_cnf
+
+--echo # Check for options overwriting
+--write_file $custom_cnf
+[mariadbd]
+innodb-flush-method=O_DIRECT
+
+[mariabackup]
+innodb-flush-method=blablabla
+EOF
+--error 13
+exec $XTRABACKUP --defaults-file=$custom_cnf --backup --target-dir=$targetdir;
+--remove_file $custom_cnf
+
+--echo # Check if uknown options that follow --mysqld-args are ingored
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --target-dir=$targetdir --mysqld-args --unknown-option;
+--rmdir $targetdir
+
+--echo # Check if [mariadb-client] group is not loaded (MDEV-22894)
+--copy_file $MYSQLTEST_VARDIR/my.cnf $custom_cnf
+--append_file $custom_cnf
+[mariadb-client]
+user=bla
+password=bla
+EOF
+exec $XTRABACKUP --defaults-file=$custom_cnf --backup --target-dir=$targetdir;
+--remove_file $custom_cnf
+--rmdir $targetdir

mysql-test/suite/mariabackup/undo_space_id.test

@@ -17,7 +17,7 @@ exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf  --backup --target-dir
 list_files $basedir undo*;
 
 --echo # xtrabackup prepare
-exec $XTRABACKUP --prepare --apply-log-only --target-dir=$basedir;
+exec $XTRABACKUP --prepare --target-dir=$basedir;
 --echo # Display undo log files from targer directory
 list_files $basedir undo*;
 

mysql-test/suite/mariabackup/xb_fulltext_encrypted.test

@@ -16,7 +16,7 @@ let $targetdir=$MYSQLTEST_VARDIR/tmp/backup;
 --disable_result_log
 
 exec $INNOBACKUPEX --defaults-file=$MYSQLTEST_VARDIR/my.cnf --no-timestamp $targetdir;
-exec $INNOBACKUPEX --apply-log --rebuild-indexes --rebuild-threads=2 $targetdir;
+exec $INNOBACKUPEX --apply-log $targetdir;
 --source include/restart_and_restore.inc
 
 --enable_result_log

mysql-test/suite/mariabackup/xb_partition.test

@@ -38,7 +38,7 @@ INSERT INTO isam_p VALUES (1), (101), (201), (301);
 let $targetdir=$MYSQLTEST_VARDIR/tmp;
 
 --disable_result_log
-exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --no-timestamp --backup --target-dir=$targetdir/full;
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --target-dir=$targetdir/full;
 --enable_result_log
 
 DROP TABLE t1;

mysys/my_getopt.c

 /*
    Copyright (c) 2002, 2013, Oracle and/or its affiliates
-   Copyright (c) 2009, 2015, MariaDB
+   Copyright (c) 2009, 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
@@ -79,6 +79,12 @@ my_bool my_getopt_skip_unknown= 0;
 */
 my_bool my_getopt_prefix_matching= 1;
 
+/*
+   This is a flag that can be set in client programs. 1 means that
+   handle_options()  will not initialize options to default values.
+*/
+my_bool my_handle_options_init_variables = 1;
+
 my_getopt_value my_getopt_get_addr= 0;
 
 static void default_reporter(enum loglevel level, const char *format, ...)
@@ -205,7 +211,8 @@ int handle_options(int *argc, char ***argv, const struct my_option *longopts,
   DBUG_ASSERT(*argv);
   (*argc)--; /* Skip the program name */
   (*argv)++; /*      --- || ----      */
-  init_variables(longopts, init_one_value);
+  if (my_handle_options_init_variables)
+    init_variables(longopts, init_one_value);
 
   is_cmdline_arg= !is_file_marker(**argv);
 

scripts/wsrep_sst_mariabackup.sh

@@ -56,8 +56,6 @@ sfmt="tar"
 strmcmd=""
 tfmt=""
 tcmd=""
-rebuild=0
-rebuildcmd=""
 payload=0
 pvformat="-F '%N => Rate:%r Avg:%a Elapsed:%t %e Bytes: %b %p' "
 pvopts="-f -i 10 -N $WSREP_SST_OPT_ROLE "
@@ -339,7 +337,6 @@ read_cnf()
     encrypt=$(parse_cnf sst encrypt 0)
     sockopt=$(parse_cnf sst sockopt "")
     progress=$(parse_cnf sst progress "")
-    rebuild=$(parse_cnf sst rebuild 0)
     ttime=$(parse_cnf sst time 0)
     cpat=$(parse_cnf sst cpat '.*galera\.cache$\|.*sst_in_progress$\|.*\.sst$\|.*gvwstate\.dat$\|.*grastate\.dat$\|.*\.err$\|.*\.log$\|.*RPM_UPGRADE_MARKER$\|.*RPM_UPGRADE_HISTORY$')
     [[ $OS == "FreeBSD" ]] && cpat=$(parse_cnf sst cpat '.*galera\.cache$|.*sst_in_progress$|.*\.sst$|.*gvwstate\.dat$|.*grastate\.dat$|.*\.err$|.*\.log$|.*RPM_UPGRADE_MARKER$|.*RPM_UPGRADE_HISTORY$')
@@ -708,7 +705,7 @@ if [[ ${FORCE_FTWRL:-0} -eq 1 ]];then
     iopts+=" --no-backup-locks "
 fi
 
-INNOEXTRA=$WSREP_SST_OPT_MYSQLD
+INNOEXTRA=
 
 INNODB_DATA_HOME_DIR=${INNODB_DATA_HOME_DIR:-""}
 # Try to set INNODB_DATA_HOME_DIR from the command line:
@@ -754,9 +751,9 @@ if [[ $ssyslog -eq 1 ]];then
             logger  -p daemon.info -t ${ssystag}wsrep-sst-$WSREP_SST_OPT_ROLE "$@" 
         }
 
-        INNOAPPLY="${INNOBACKUPEX_BIN} --innobackupex $disver $iapts \$INNOEXTRA --apply-log \$rebuildcmd \${DATA} 2>&1 | logger -p daemon.err -t ${ssystag}innobackupex-apply"
-        INNOMOVE="${INNOBACKUPEX_BIN} --innobackupex ${WSREP_SST_OPT_CONF} $disver $impts  --move-back --force-non-empty-directories \${DATA} 2>&1 | logger -p daemon.err -t ${ssystag}innobackupex-move"
-        INNOBACKUP="${INNOBACKUPEX_BIN} --innobackupex ${WSREP_SST_OPT_CONF} $disver $iopts \$tmpopts \$INNOEXTRA --galera-info --stream=\$sfmt \$itmpdir 2> >(logger -p daemon.err -t ${ssystag}innobackupex-backup)"
+        INNOAPPLY="${INNOBACKUPEX_BIN} --prepare $disver $iapts \$INNOEXTRA --target-dir=\${DATA} --mysqld-args \$WSREP_SST_OPT_MYSQLD  2>&1 | logger -p daemon.err -t ${ssystag}innobackupex-apply"
+        INNOMOVE="${INNOBACKUPEX_BIN} ${WSREP_SST_OPT_CONF} --move-back $disver $impts --force-non-empty-directories --target-dir=\${DATA} 2>&1 | logger -p daemon.err -t ${ssystag}innobackupex-move"
+        INNOBACKUP="${INNOBACKUPEX_BIN} ${WSREP_SST_OPT_CONF} --backup $disver $iopts \$tmpopts \$INNOEXTRA --galera-info --stream=\$sfmt --target-dir=\$itmpdir --mysqld-args \$WSREP_SST_OPT_MYSQLD 2> >(logger -p daemon.err -t ${ssystag}innobackupex-backup)"
     fi
 
 else
@@ -818,9 +815,9 @@ then
 
 fi
  
-    INNOAPPLY="${INNOBACKUPEX_BIN} --innobackupex $disver $iapts \$INNOEXTRA --apply-log \$rebuildcmd \${DATA} &> ${INNOAPPLYLOG}"
-    INNOMOVE="${INNOBACKUPEX_BIN} --innobackupex ${WSREP_SST_OPT_CONF} $disver $impts  --move-back --force-non-empty-directories \${DATA} &> ${INNOMOVELOG}"
-    INNOBACKUP="${INNOBACKUPEX_BIN} --innobackupex ${WSREP_SST_OPT_CONF} $disver $iopts \$tmpopts \$INNOEXTRA --galera-info --stream=\$sfmt \$itmpdir 2> ${INNOBACKUPLOG}"
+    INNOAPPLY="${INNOBACKUPEX_BIN} --prepare $disver $iapts \$INNOEXTRA --target-dir=\${DATA} --mysqld-args \$WSREP_SST_OPT_MYSQLD &> ${INNOAPPLYLOG}"
+    INNOMOVE="${INNOBACKUPEX_BIN} ${WSREP_SST_OPT_CONF} --move-back $disver $impts  --move-back --force-non-empty-directories --target-dir=\${DATA} &> ${INNOMOVELOG}"
+    INNOBACKUP="${INNOBACKUPEX_BIN} ${WSREP_SST_OPT_CONF} --backup $disver $iopts \$tmpopts \$INNOEXTRA --galera-info --stream=\$sfmt --target-dir=\$itmpdir --mysqld-args \$WSREP_SST_OPT_MYSQLD 2> ${INNOBACKUPLOG}"
 fi
 
 get_stream
@@ -862,15 +859,6 @@ then
            INNOEXTRA+=" --password="
         fi
 
-        get_keys
-        if [[ $encrypt -eq 1 ]];then
-            if [[ -n $ekey ]];then
-                INNOEXTRA+=" --encrypt=$ealgo --encrypt-key=$ekey"
-            else 
-                INNOEXTRA+=" --encrypt=$ealgo --encrypt-key-file=$ekeyfile"
-            fi
-        fi
-
         check_extra
 
         wsrep_log_info "Streaming GTID file before SST"
@@ -1091,18 +1079,6 @@ then
             exit 2
         fi
 
-        # Rebuild indexes for compact backups
-        if grep -q 'compact = 1' ${DATA}/xtrabackup_checkpoints;then 
-            wsrep_log_info "Index compaction detected"
-            rebuild=1
-        fi
-
-        if [[ $rebuild -eq 1 ]];then 
-            nthreads=$(parse_cnf xtrabackup rebuild-threads $nproc)
-            wsrep_log_info "Rebuilding during prepare with $nthreads threads"
-            rebuildcmd="--rebuild-indexes --rebuild-threads=$nthreads"
-        fi
-
         if test -n "$(find ${DATA} -maxdepth 1 -type f -name '*.qp' -print -quit)";then
 
             wsrep_log_info "Compressed qpress files found"

sql/encryption.cc

@@ -18,6 +18,7 @@
 #include "log.h"
 #include "sql_plugin.h"
 #include <my_crypt.h>
+#include <violite.h>
 
 /* there can be only one encryption plugin enabled */
 static plugin_ref encryption_manager= 0;
@@ -63,6 +64,8 @@ int initialize_encryption_plugin(st_plugin_int *plugin)
   if (encryption_manager)
     return 1;
 
+  vio_check_ssl_init();
+
   if (plugin->plugin->init && plugin->plugin->init(plugin))
   {
     sql_print_error("Plugin '%s' init function returned error.",

sql/opt_range.cc

@@ -15942,15 +15942,6 @@ static void print_key_value(String *out, const KEY_PART_INFO *key_part,
   {
     field= key_part->field;
     store_length= key_part->store_length;
-    if (field->flags & BLOB_FLAG)
-    {
-      // Byte 0 of a nullable key is the null-byte. If set, key is NULL.
-      if (field->real_maybe_null() && *key)
-      {
-        out->append(STRING_WITH_LEN("NULL"));
-        goto next;
-      }
-    }
 
     if (field->real_maybe_null())
     {

sql/rpl_parallel.cc

@@ -467,6 +467,7 @@ pool_mark_busy(rpl_parallel_thread_pool *pool, THD *thd)
     So we protect the infrequent operations of FLUSH TABLES WITH READ LOCK and
     pool size changes with this condition wait.
   */
+  DBUG_EXECUTE_IF("mark_busy_mdev_22370",my_sleep(1000000););
   mysql_mutex_lock(&pool->LOCK_rpl_thread_pool);
   if (thd)
   {
@@ -2012,10 +2013,24 @@ rpl_parallel_thread_pool::init(uint32 size)
 
 void
 rpl_parallel_thread_pool::destroy()
+{
+  deactivate();
+  destroy_cond_mutex();
+}
+
+void
+rpl_parallel_thread_pool::deactivate()
 {
   if (!inited)
     return;
   rpl_parallel_change_thread_count(this, 0, 1);
+}
+
+void
+rpl_parallel_thread_pool::destroy_cond_mutex()
+{
+  if (!inited)
+    return;
   mysql_mutex_destroy(&LOCK_rpl_thread_pool);
   mysql_cond_destroy(&COND_rpl_thread_pool);
   inited= false;

sql/rpl_parallel.h

@@ -244,6 +244,8 @@ struct rpl_parallel_thread_pool {
   rpl_parallel_thread_pool();
   int init(uint32 size);
   void destroy();
+  void deactivate();
+  void destroy_cond_mutex();
   struct rpl_parallel_thread *get_thread(rpl_parallel_thread **owner,
                                          rpl_parallel_entry *entry);
   void release_thread(rpl_parallel_thread *rpt);

sql/slave.cc

@@ -1448,7 +1448,7 @@ void slave_prepare_for_shutdown()
   mysql_mutex_unlock(&LOCK_active_mi);
   // It's safe to destruct worker pool now when
   // all driver threads are gone.
-  global_rpl_thread_pool.destroy();
+  global_rpl_thread_pool.deactivate();
   stop_slave_background_thread();
 }
 

storage/innobase/btr/btr0pcur.cc

@@ -158,7 +158,7 @@ btr_pcur_store_position(
 			ut_ad(index->is_instant());
 			ut_ad(page_get_n_recs(block->frame) == 1);
 			ut_ad(page_is_leaf(block->frame));
-			ut_ad(!page_has_siblings(block->frame));
+			ut_ad(!page_has_prev(block->frame));
 			cursor->rel_pos = BTR_PCUR_AFTER_LAST_IN_TREE;
 			return;
 		}

storage/innobase/trx/trx0trx.cc

@@ -840,14 +840,9 @@ static trx_rseg_t* trx_assign_rseg_low()
 
 	/* Choose a rollback segment evenly distributed between 0 and
 	innodb_undo_logs-1 in a round-robin fashion, skipping those
-	undo tablespaces that are scheduled for truncation.
-
-	Because rseg_slot is not protected by atomics or any mutex, race
-	conditions are possible, meaning that multiple transactions
-	that start modifications concurrently will write their undo
-	log to the same rollback segment. */
-	static ulong	rseg_slot;
-	ulint		slot = rseg_slot++ % TRX_SYS_N_RSEGS;
+	undo tablespaces that are scheduled for truncation. */
+	static Atomic_counter<unsigned>	rseg_slot;
+	unsigned slot = rseg_slot++ % TRX_SYS_N_RSEGS;
 	ut_d(if (trx_rseg_n_slots_debug) slot = 0);
 	trx_rseg_t*	rseg;
 
@@ -926,11 +921,8 @@ trx_t::assign_temp_rseg()
 	compile_time_assert(ut_is_2pow(TRX_SYS_N_RSEGS));
 
 	/* Choose a temporary rollback segment between 0 and 127
-	in a round-robin fashion. Because rseg_slot is not protected by
-	atomics or any mutex, race conditions are possible, meaning that
-	multiple transactions that start modifications concurrently
-	will write their undo log to the same rollback segment. */
-	static ulong	rseg_slot;
+	in a round-robin fashion. */
+	static Atomic_counter<unsigned> rseg_slot;
 	trx_rseg_t*	rseg = trx_sys.temp_rsegs[
 		rseg_slot++ & (TRX_SYS_N_RSEGS - 1)];
 	ut_ad(!rseg->is_persistent());

vio/viosslfactories.c

@@ -150,7 +150,7 @@ vio_set_cert_stuff(SSL_CTX *ctx, const char *cert_file, const char *key_file,
 }
 
 
-static void check_ssl_init()
+void vio_check_ssl_init()
 {
   if (!ssl_algorithms_added)
   {
@@ -243,7 +243,7 @@ new_VioSSLFd(const char *key_file, const char *cert_file,
               crl_file ? crl_file : "NULL",
               crl_path ? crl_path : "NULL"));
 
-  check_ssl_init();
+  vio_check_ssl_init();
 
   if (!(ssl_fd= ((struct st_VioSSLFd*)
                  my_malloc(key_memory_vio_ssl_fd,