Jan Lindström f219fb8489 MDEV-35355 : Galera test failure on galera_sr.mysql-wsrep-features#165 ...

Problem was that in DeadlockChecker::trx_rollback() we hold lock_sys
before we call wsrep_handle_SR_rollback() where THD::LOCK_thd_data
(and some cases THD::LOCK_thd_kill) are acquired. This is against
current mutex ordering rules.

However, acquiring THD::LOCK_thd_data is not necessary because we
always are in victim_thd context, either client session is rolling
back or rollbacker thread should be in control. Therefore, we should
always use wsrep_thd_self_abort() and then no additional mutexes are
required.

Fixed by removing locking of THD::LOCK_thd_data and using only
wsrep_thd_self_abort(). In debug builds added assertions to
verify that we are always in victim_thd context.

This fix is for MariaDB 10.5 and we already have a test case
that sporadically fail in Jenkins before this fix.

Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>

2024-12-03 03:19:35 +01:00

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