From 5506768c52965240c3defda9cf673df00c7febe1 Mon Sep 17 00:00:00 2001 From: Sergey Vojtovich Date: Tue, 6 May 2014 12:13:03 +0400 Subject: [PATCH] MDEV-6083 - Assertion `! (&(&LOCK_open)->m_mutex)->count || ! pthread_equal(pth read_self(), (&(&LOCK_open)->m_mutex)->thread)' fails in intern_sys_var_ptr on server shutdown after uninstalling TokuDB plugin at runtime This assertion was introduced by patch for MDEV-5089 to ensure proper lock order among LOCK_open and LOCK_global_system_variables: LOCK_open must not be held while acquiring LOCK_global_system_variables. intern_sys_var_ptr() may be called while freeing storage engine variables with PLUGIN_VAR_MEMALLOC flag (when destroying table share after storage engine was uninstalled). In this case LOCK_open is held, which is harmless because we need global value pointer and thus won't acquire LOCK_global_system_variables. Relaxed assertion so it is valid only for session variables. --- sql/sql_plugin.cc | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/sql/sql_plugin.cc b/sql/sql_plugin.cc index 56f335c2359..fc856f11a89 100644 --- a/sql/sql_plugin.cc +++ b/sql/sql_plugin.cc @@ -2900,11 +2900,12 @@ static uchar *intern_sys_var_ptr(THD* thd, int offset, bool global_lock) DBUG_ENTER("intern_sys_var_ptr"); DBUG_ASSERT(offset >= 0); DBUG_ASSERT((uint)offset <= global_system_variables.dynamic_variables_head); - mysql_mutex_assert_not_owner(&LOCK_open); if (!thd) DBUG_RETURN((uchar*) global_system_variables.dynamic_variables_ptr + offset); + mysql_mutex_assert_not_owner(&LOCK_open); + /* dynamic_variables_head points to the largest valid offset */