From 3e8f51bbf309e3b6b161bb3f7212cc3e4468ba6f Mon Sep 17 00:00:00 2001
From: Johan Wikman <johan.wikman@mariadb.com>
Date: Wed, 7 Mar 2018 16:04:53 +0200
Subject: [PATCH] MXS-1705 Make note of workers only after creation

The variable containing the number of workers must be updated
only after the workers have been successfully created.

Failure to do this led to crash in Worker::shutdown_all() if a
terminating signal was received after the worker initialization
had failed.
---
 server/core/worker.cc | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/server/core/worker.cc b/server/core/worker.cc
index f957ac8af..f5d963b7f 100644
--- a/server/core/worker.cc
+++ b/server/core/worker.cc
@@ -182,7 +182,6 @@ bool Worker::init()
 {
     ss_dassert(!this_unit.initialized);
 
-    this_unit.n_workers = config_threadcount();
     this_unit.number_poll_spins = config_nbpolls();
     this_unit.max_poll_sleep = config_pollsleep();
 
@@ -190,33 +189,37 @@ bool Worker::init()
 
     if (this_unit.epoll_listener_fd != -1)
     {
-        this_unit.ppWorkers = new (std::nothrow) Worker* [this_unit.n_workers] (); // Zero initialized array
+        int n_workers = config_threadcount();
+        Worker** ppWorkers = new (std::nothrow) Worker* [n_workers] (); // Zero initialized array
 
-        if (this_unit.ppWorkers)
+        if (ppWorkers)
         {
-            for (int i = 0; i < this_unit.n_workers; ++i)
+            for (int i = 0; i < n_workers; ++i)
             {
                 Worker* pWorker = Worker::create(i, this_unit.epoll_listener_fd);
 
                 if (pWorker)
                 {
-                    this_unit.ppWorkers[i] = pWorker;
+                    ppWorkers[i] = pWorker;
                 }
                 else
                 {
                     for (int j = i - 1; j >= 0; --j)
                     {
-                        delete this_unit.ppWorkers[j];
+                        delete ppWorkers[j];
                     }
 
-                    delete this_unit.ppWorkers;
-                    this_unit.ppWorkers = NULL;
+                    delete [] ppWorkers;
+                    ppWorkers = NULL;
                     break;
                 }
             }
 
-            if (this_unit.ppWorkers)
+            if (ppWorkers)
             {
+                this_unit.ppWorkers = ppWorkers;
+                this_unit.n_workers = n_workers;
+
                 this_unit.initialized = true;
             }
         }
@@ -931,10 +934,12 @@ void Worker::shutdown()
 void Worker::shutdown_all()
 {
     // NOTE: No logging here, this function must be signal safe.
+    ss_dassert((this_unit.n_workers == 0) || (this_unit.ppWorkers != NULL));
 
     for (int i = 0; i < this_unit.n_workers; ++i)
     {
         Worker* pWorker = this_unit.ppWorkers[i];
+        ss_dassert(pWorker);
 
         pWorker->shutdown();
     }