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MDEV-13549 Wrong usage of mutex 'LOCK_wsrep_thd' and 'LOCK_thd_kill' test galera.MW-286

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Test MW-286 occasionally failed with error the following message:

```
safe_mutex: Found wrong usage of mutex 'LOCK_wsrep_thd' and 'LOCK_thd_kill'
Mutex currently locked (in reverse order):
LOCK_thd_kill                     mariadb-server/sql/sql_class.h  line 3535
LOCK_wsrep_thd                    mariadb-server/sql/wsrep_thd.cc  line 88
```

The fix consists in calling thd->reset_killed() in wsrep_mysql_parse() after
LOCK_wsrep_thd is unlocked. Which avoids the taking locks LOCK_wsrep_thd and
LOCK_thd_kill in reverse order.
This commit is contained in:
Daniele Sciascia 2018-03-08 11:11:03 +01:00
parent 0f0776b2ad
commit a3ba3aab5a
1 changed files with 3 additions and 3 deletions
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6
sql/sql_parse.cc
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@ -7193,7 +7193,6 @@ static void wsrep_mysql_parse(THD *thd, char *rawbuf, uint length,
thd->wsrep_conflict_state == CERT_FAILURE)
{
thd->reset_for_next_command();
thd->reset_killed();
if (is_autocommit &&
thd->lex->sql_command != SQLCOM_SELECT &&
(thd->wsrep_retry_counter < thd->variables.wsrep_retry_autocommit))
@ -7221,17 +7220,18 @@ static void wsrep_mysql_parse(THD *thd, char *rawbuf, uint length,
thd->thread_id, is_autocommit, thd->wsrep_retry_counter,
thd->variables.wsrep_retry_autocommit, thd->query());
my_error(ER_LOCK_DEADLOCK, MYF(0), "wsrep aborted transaction");
thd->reset_killed();
thd->wsrep_conflict_state= NO_CONFLICT;
if (thd->wsrep_conflict_state != REPLAYING)
thd->wsrep_retry_counter= 0; // reset
}
mysql_mutex_unlock(&thd->LOCK_wsrep_thd);
thd->reset_killed();
}
else
{
set_if_smaller(thd->wsrep_retry_counter, 0); // reset; eventually ok
mysql_mutex_unlock(&thd->LOCK_wsrep_thd);
}
mysql_mutex_unlock(&thd->LOCK_wsrep_thd);
}
/* If retry is requested clean up explain structure */