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| author | Marko Mäkelä <marko.makela@mariadb.com> | 2019-03-27 15:00:12 +0200 |
|---|---|---|
| committer | Marko Mäkelä <marko.makela@mariadb.com> | 2019-03-27 15:00:12 +0200 |
| commit | f3ff45f955ec90d22c0c94d11451d6e36b48b7eb (patch) | |
| tree | 42ce3d3491d0c1426b1657d516d318e5e7151b91 | |
| parent | 349560d5d5e53966fe75eef2bfefd12e29278f6a (diff) | |
| download | mariadb-git-f3ff45f955ec90d22c0c94d11451d6e36b48b7eb.tar.gz | |
MDEV-15658: Assertion failed in lock_rec_other_trx_holds_expl_callback
Fix a race condition that was introduced in debug code by MDEV-14638.
lock_rec_other_trx_holds_expl(): After acquiring the lock_sys->mutex,
check if the transaction might have been committed. Otherwise,
the assertion in the trx_sys.rw_trx_hash traversal callback could fail.
| -rw-r--r-- | storage/innobase/lock/lock0lock.cc | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/storage/innobase/lock/lock0lock.cc b/storage/innobase/lock/lock0lock.cc index c8707955a5d..8414ed82e34 100644 --- a/storage/innobase/lock/lock0lock.cc +++ b/storage/innobase/lock/lock0lock.cc @@ -1,7 +1,7 @@ /***************************************************************************** Copyright (c) 1996, 2017, Oracle and/or its affiliates. All Rights Reserved. -Copyright (c) 2014, 2018, MariaDB Corporation. +Copyright (c) 2014, 2019, MariaDB Corporation. 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 the Free Software @@ -5527,6 +5527,20 @@ static void lock_rec_other_trx_holds_expl(trx_t *caller_trx, trx_t *trx, { ut_ad(!page_rec_is_metadata(rec)); lock_mutex_enter(); + ut_ad(trx->is_referenced()); + /* Prevent a data race with trx_prepare(), which could change the + state from ACTIVE to PREPARED. Other state changes should be + blocked by lock_mutex_own() and trx->is_referenced(). */ + trx_mutex_enter(trx); + const trx_state_t state = trx->state; + trx_mutex_exit(trx); + ut_ad(state != TRX_STATE_NOT_STARTED); + if (state == TRX_STATE_COMMITTED_IN_MEMORY) + { + /* The transaction was committed before our lock_mutex_enter(). */ + lock_mutex_exit(); + return; + } lock_rec_other_trx_holds_expl_arg arg= { page_rec_get_heap_no(rec), block, trx }; trx_sys.rw_trx_hash.iterate(caller_trx, |