Merge pull request #2846 from sysown/v2.1.0-2834

Fixes #2834: Segfault due to invalid access to threads during startup / shutdown

include/MySQL_Thread.h

@@ -505,6 +505,7 @@ class MySQL_Threads_Handler
 	} variables;
 	struct {
 		unsigned int mirror_sessions_current;
+		int threads_initialized = 0;
 		/// Prometheus metrics arrays
 		std::array<prometheus::Counter*, p_th_counter::__size> p_counter_array {};
 		std::array<prometheus::Gauge*, p_th_gauge::__size> p_gauge_array {};

lib/MySQL_Thread.cpp

@@ -5747,6 +5747,7 @@ __exit_kill_session:
 }
 
 unsigned long long MySQL_Threads_Handler::get_total_mirror_queue() {
+	if ((__sync_fetch_and_add(&status_variables.threads_initialized, 0) == 0) || this->shutdown_) return 0;
 	unsigned long long q=0;
 	unsigned int i;
 	for (i=0;i<num_threads;i++) {
@@ -5763,6 +5764,7 @@ unsigned long long MySQL_Threads_Handler::get_total_mirror_queue() {
 
 
 unsigned long long MySQL_Threads_Handler::get_status_variable(enum MySQL_Thread_status_variable v_idx, p_th_counter::metric m_idx) {
+	if ((__sync_fetch_and_add(&status_variables.threads_initialized, 0) == 0) || this->shutdown_) return 0;
 	unsigned long long q=0;
 	unsigned int i;
 	for (i=0;i<num_threads;i++) {
@@ -5781,6 +5783,7 @@ unsigned long long MySQL_Threads_Handler::get_status_variable(enum MySQL_Thread_
 }
 
 unsigned int MySQL_Threads_Handler::get_active_transations() {
+	if ((__sync_fetch_and_add(&status_variables.threads_initialized, 0) == 0) || this->shutdown_) return 0;
 	unsigned long long q=0;
 	unsigned int i;
 	for (i=0;i<num_threads;i++) {
@@ -5797,6 +5800,7 @@ unsigned int MySQL_Threads_Handler::get_active_transations() {
 
 #ifdef IDLE_THREADS
 unsigned int MySQL_Threads_Handler::get_non_idle_client_connections() {
+	if ((__sync_fetch_and_add(&status_variables.threads_initialized, 0) == 0) || this->shutdown_) return 0;
 	unsigned long long q=0;
 	unsigned int i;
 	for (i=0;i<num_threads;i++) {
@@ -5813,6 +5817,7 @@ unsigned int MySQL_Threads_Handler::get_non_idle_client_connections() {
 #endif // IDLE_THREADS
 
 unsigned long long MySQL_Threads_Handler::get_mysql_backend_buffers_bytes() {
+	if ((__sync_fetch_and_add(&status_variables.threads_initialized, 0) == 0) || this->shutdown_) return 0;
 	unsigned long long q=0;
 	unsigned int i;
 	for (i=0;i<num_threads;i++) {
@@ -5829,6 +5834,7 @@ unsigned long long MySQL_Threads_Handler::get_mysql_backend_buffers_bytes() {
 }
 
 unsigned long long MySQL_Threads_Handler::get_mysql_frontend_buffers_bytes() {
+	if ((__sync_fetch_and_add(&status_variables.threads_initialized, 0) == 0) || this->shutdown_) return 0;
 	unsigned long long q=0;
 	unsigned int i;
 	for (i=0;i<num_threads;i++) {
@@ -5854,6 +5860,7 @@ unsigned long long MySQL_Threads_Handler::get_mysql_frontend_buffers_bytes() {
 }
 
 unsigned long long MySQL_Threads_Handler::get_mysql_session_internal_bytes() {
+	if ((__sync_fetch_and_add(&status_variables.threads_initialized, 0) == 0) || this->shutdown_) return 0;
 	unsigned long long q=0;
 	unsigned int i;
 	for (i=0;i<num_threads;i++) {

src/main.cpp

@@ -1372,6 +1372,7 @@ void ProxySQL_Main_init_phase3___start_all() {
 
 	do { /* nothing */ } while (load_ != 1);
 	load_ = 0;
+	__sync_fetch_and_add(&GloMTH->status_variables.threads_initialized, 1);
 
 	{
 		cpu_timer t;