From b51c8cab3e0afccd6b44fea70e59243b24844158 Mon Sep 17 00:00:00 2001 From: Sergey Vojtovich Date: Fri, 20 Aug 2010 13:58:28 +0400 Subject: BUG#54989 - With null_audit installed, server hangs on an attempt to install a plugin twice Server crashes when [UN]INSTALL PLUGIN fails (returns an error) and general log is disabled and there are audit plugins interested in MYSQL_AUDIT_GENERAL_CLASS. When audit event is triggered, audit subsystem acquires interested plugins by walking through plugin list. Evidently plugin list iterator protects plugin list by acquiring LOCK_plugin, see plugin_foreach_with_mask(). On the other hand [UN]INSTALL PLUGIN is acquiring LOCK_plugin rather for a long time. When audit event is triggered during [UN]INSTALL PLUGIN, plugin list iterator acquires the same lock (within the same thread) second time. Repeatable only with general_log disabled, because general_log triggers MYSQL_AUDIT_GENERAL_LOG event, which acquires audit plugins before [UN]INSTALL PLUGIN acquired LOCK_plugin. With this fix we pre-acquire audit plugins for events that may potentially occur during [UN]INSTALL PLUGIN. This hack should be removed when LOCK_plugin is fixed so it protects only what it supposed to protect. No test case for this fix - we do not have facility to test audit plugins yet. sql/sql_audit.cc: Move "acquire audit plugin" logics to a separate function. sql/sql_audit.h: Move "acquire audit plugin" logics to a separate function. sql/sql_plugin.cc: Pre-acquire audit plugins for events that may potentially occur during [UN]INSTALL PLUGIN. --- sql/sql_audit.h | 1 + 1 file changed, 1 insertion(+) (limited to 'sql/sql_audit.h') diff --git a/sql/sql_audit.h b/sql/sql_audit.h index 5b6962b9ecb..953e41f1f06 100644 --- a/sql/sql_audit.h +++ b/sql/sql_audit.h @@ -29,6 +29,7 @@ extern void mysql_audit_finalize(); extern void mysql_audit_init_thd(THD *thd); extern void mysql_audit_free_thd(THD *thd); +extern void mysql_audit_acquire_plugins(THD *thd, uint event_class); extern void mysql_audit_notify(THD *thd, uint event_class, -- cgit v1.2.1