From 4280b84e6a1fadc168474f94547cfb5e4cf4aa8a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Canna=C3=B2?= <rene.cannao@gmail.com>
Date: Wed, 1 May 2019 17:16:02 +1000
Subject: [PATCH] Fix crash on startup when calling Get_Memory_Stats #2037

---
 lib/MySQL_Thread.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/MySQL_Thread.cpp b/lib/MySQL_Thread.cpp
index 432a2638b..1227c2d0d 100644
--- a/lib/MySQL_Thread.cpp
+++ b/lib/MySQL_Thread.cpp
@@ -4415,10 +4415,12 @@ void MySQL_Threads_Handler::Get_Memory_Stats() {
 	for (i=0;i<j;i++) {
 		if (i<num_threads) {
 			thr=(MySQL_Thread *)mysql_threads[i].worker;
+			if (thr==NULL) return; // quick exit, at least one thread is not ready
 #ifdef IDLE_THREADS
 		} else {
 			if (GloVars.global.idle_threads) {
 				thr=(MySQL_Thread *)mysql_threads_idles[i-num_threads].worker;
+				if (thr==NULL) return; // quick exit, at least one thread is not ready
 			}
 #endif // IDLE_THREADS
 		}
@@ -4711,6 +4713,7 @@ void MySQL_Threads_Handler::signal_all_threads(unsigned char _c) {
 	if (mysql_threads==0) return;
 	for (i=0;i<num_threads;i++) {
 		MySQL_Thread *thr=(MySQL_Thread *)mysql_threads[i].worker;
+		if (thr==NULL) return; // quick exit, at least one thread is not ready
 		int fd=thr->pipefd[1];
 		if (write(fd,&c,1)==-1) {
 			proxy_error("Error during write in signal_all_threads()\n");
@@ -4720,6 +4723,7 @@ void MySQL_Threads_Handler::signal_all_threads(unsigned char _c) {
 	if (GloVars.global.idle_threads)
 	for (i=0;i<num_threads;i++) {
 		MySQL_Thread *thr=(MySQL_Thread *)mysql_threads_idles[i].worker;
+		if (thr==NULL) return; // quick exit, at least one thread is not ready
 		int fd=thr->pipefd[1];
 		if (write(fd,&c,1)==-1) {
 			proxy_error("Error during write in signal_all_threads()\n");