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BUG#14485479: INSTALL AUDIT PLUGIN HANGS IF WE TRY TO

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DISABLE AND ENABLED DURING DDL OPERATION

PROBLEM: Same thread trying to acquire the same mutex
         second time leads to hang/server crash.
         While [un]installing audit_log plugin
         a thread acquires the LOCK_plugin mutex
         and after successful initialization tries
         to write in mysql.plugin table. It holds
         this mutex for a long time. If some how
         plugin table is corrupted then a write to 
         plugin table will throw an error, thread try
         to log this error in the audit_log plugin,
         doing so it tries to acquire the mutex
         again and results is server hang/crash.

SOLUTION: Releasing the LOCK_plugin mutex before
          writing in mysql.plugin table. We dont
          need to hold this mutex as thread already
          acquired a TL_WRITE lock on mysql.plugin
          table.
This commit is contained in:
Ashish Agarwal 2012-10-31 12:40:48 +05:30
parent fa3e181d62
commit 147be51f20
3 changed files with 26 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
mysql-test/include/have_null_audit_plugin.inc Normal file
View File

@ -0,0 +1,22 @@
disable_query_log;
#
# Check if server has support for loading plugins
#
if (`SELECT @@have_dynamic_loading != 'YES'`) {
--skip Null audit plugin requires dynamic loading
}
#
# Check if the variable AUDIT_NULL is set
#
if (!$AUDIT_NULL) {
--skip Audit_null plugin requires the environment variable \$AUDIT_NULL to be set (normally done by mtr)
}
#
# Check if --plugin-dir was setup for null_audit db
#
if (`SELECT CONCAT('--plugin-dir=', REPLACE(@@plugin_dir, '\\\\', '/')) != '$AUDIT_NULL_OPT/'`) {
--skip null audit plugin requires that --plugin-dir is set to the null audit plugin dir (either the .opt file does not contain \$AUDIT_NULL_OPT or another plugin is in use)
}
enable_query_log;

1
mysql-test/include/plugin.defs
View File

@ -40,3 +40,4 @@ ha_blackhole storage/blackhole BLACKHOLE_PLUGIN
ha_federated storage/federated FEDERATED_PLUGIN
mypluglib plugin/fulltext SIMPLE_PARSER
libdaemon_example plugin/daemon_example DAEMONEXAMPLE
adt_null plugin/audit_null AUDIT_NULL

5
sql/sql_plugin.cc
View File

@ -1820,6 +1820,7 @@ bool mysql_install_plugin(THD *thd, const LEX_STRING *name, const LEX_STRING *dl
{
if (plugin_initialize(tmp))
{
mysql_mutex_unlock(&LOCK_plugin);
my_error(ER_CANT_INITIALIZE_UDF, MYF(0), name->str,
"Plugin initialization function failed.");
goto deinit;
@ -1831,6 +1832,7 @@ bool mysql_install_plugin(THD *thd, const LEX_STRING *name, const LEX_STRING *dl
of the insert into the plugin table, so that it is not replicated in
row based mode.
*/
mysql_mutex_unlock(&LOCK_plugin);
tmp_disable_binlog(thd);
table->use_all_columns();
restore_record(table, s->default_values);
@ -1843,10 +1845,9 @@ bool mysql_install_plugin(THD *thd, const LEX_STRING *name, const LEX_STRING *dl
table->file->print_error(error, MYF(0));
goto deinit;
}
mysql_mutex_unlock(&LOCK_plugin);
DBUG_RETURN(FALSE);
deinit:
mysql_mutex_lock(&LOCK_plugin);
tmp->state= PLUGIN_IS_DELETED;
reap_needed= true;
reap_plugins();