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MDEV-3984: Double free of Master_info * when CHANGE MASTER fails.

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When CHANGE MASTER fails, it may or may not have already added
the Master_info * to the index. Implement logic that properly
handles removal and freeing in both cases.
This commit is contained in:
unknown 2013-01-30 15:11:36 +01:00
parent 6f2680a73c
commit ea5632e9d7
5 changed files with 31 additions and 7 deletions
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4
mysql-test/suite/multi_source/multisource.result
View File

@ -1,3 +1,7 @@
change master 'abc' to relay_log_file='';
ERROR HY000: Failed initializing relay log position: Could not find target log during relay log initialization
change master 'abc2' to master_host='';
ERROR HY000: Incorrect arguments to MASTER_HOST
change master 'master1' to
master_port=MYPORT_1,
master_host='127.0.0.1',

9
mysql-test/suite/multi_source/multisource.test
View File

@ -8,6 +8,15 @@
--connect (slave,127.0.0.1,root,,,$SERVER_MYPORT_3)
# MDEV-3984: crash/read of freed memory when changing master with named connection
# This fails after adding the new master 'abc', check we do not free twice.
--error ER_RELAY_LOG_INIT
change master 'abc' to relay_log_file='';
# This fails before adding the new master, check that we do free it.
--error ER_WRONG_ARGUMENTS
change master 'abc2' to master_host='';
# Start replication from the first master
--replace_result $SERVER_MYPORT_1 MYPORT_1

15
sql/sql_parse.cc
View File

@ -2393,6 +2393,7 @@ case SQLCOM_PREPARE:
LEX_MASTER_INFO *lex_mi= &thd->lex->mi;
Master_info *mi;
bool new_master= 0;
bool master_info_added;
if (check_global_access(thd, SUPER_ACL))
goto error;
@ -2415,15 +2416,19 @@ case SQLCOM_PREPARE:
new_master= 1;
}
res= change_master(thd, mi);
res= change_master(thd, mi, &master_info_added);
if (res && new_master)
{
/*
The new master was added by change_master(). Remove it as it didn't
work.
If the new master was added by change_master(), remove it as it didn't
work (this will free mi as well).
If new master was not added, we still need to free mi.
*/
master_info_index->remove_master_info(&lex_mi->connection_name);
delete mi;
if (master_info_added)
master_info_index->remove_master_info(&lex_mi->connection_name);
else
delete mi;
}
mysql_mutex_unlock(&LOCK_active_mi);

8
sql/sql_repl.cc
View File

@ -1677,10 +1677,14 @@ static bool get_string_parameter(char *to, const char *from, size_t length,
@param mi Pointer to Master_info object belonging to the slave's IO
thread.
@param master_info_added Out parameter saying if the Master_info *mi was
added to the global list of masters. This is useful in error conditions
to know if caller should free Master_info *mi.
@retval FALSE success
@retval TRUE error
*/
bool change_master(THD* thd, Master_info* mi)
bool change_master(THD* thd, Master_info* mi, bool *master_info_added)
{
int thread_mask;
const char* errmsg= 0;
@ -1695,6 +1699,7 @@ bool change_master(THD* thd, Master_info* mi)
LEX_MASTER_INFO* lex_mi= &thd->lex->mi;
DBUG_ENTER("change_master");
*master_info_added= false;
/*
We need to check if there is an empty master_host. Otherwise
change master succeeds, a master.info file is created containing
@ -1743,6 +1748,7 @@ bool change_master(THD* thd, Master_info* mi)
ret= TRUE;
goto err;
}
*master_info_added= true;
}
if (global_system_variables.log_warnings > 1)
sql_print_information("Master: '%.*s' Master_info_file: '%s' "

2
sql/sql_repl.h
View File

@ -41,7 +41,7 @@ extern my_bool opt_sporadic_binlog_dump_fail;
int start_slave(THD* thd, Master_info* mi, bool net_report);
int stop_slave(THD* thd, Master_info* mi, bool net_report);
bool change_master(THD* thd, Master_info* mi);
bool change_master(THD* thd, Master_info* mi, bool *master_info_added);
bool mysql_show_binlog_events(THD* thd);
int reset_slave(THD *thd, Master_info* mi);
int reset_master(THD* thd);