From 8dcb4bc3cce1f487cfac65ed20d21378d0f39b2e Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Wed, 29 Aug 2012 16:43:01 +0200 Subject: [PATCH 1/1] Terminate threads before to exit main() It is very difficult and risky to assure that a running thread doesn't access a global variable. This is currently true, but could change in the future and we don't want to rely on code that works 'by accident'. The threads are still running when ThreadPool destructor is called (after main() returns) and this could lead to crashes if a thread accesses a global that has been already freed. The solution is to use an exit() function and call it while we are still in main(), ensuring global variables are still alive at threads termination time. No functional change. Signed-off-by: Marco Costalba --- src/main.cpp | 4 +++- src/thread.cpp | 4 ++-- src/thread.h | 4 ++-- 3 files changed, 7 insertions(+), 5 deletions(-) diff --git a/src/main.cpp b/src/main.cpp index ad68ca35..e4ebcc30 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -37,8 +37,8 @@ int main(int argc, char* argv[]) { Zobrist::init(); Bitbases::init_kpk(); Search::init(); - Threads.init(); Eval::init(); + Threads.init(); TT.set_size(Options["Hash"]); std::string args; @@ -47,4 +47,6 @@ int main(int argc, char* argv[]) { args += std::string(argv[i]) + " "; UCI::loop(args); + + Threads.exit(); } diff --git a/src/thread.cpp b/src/thread.cpp index 541610a1..50412468 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -196,9 +196,9 @@ void ThreadPool::init() { } -// d'tor cleanly terminates the threads when the program exits. +// exit() cleanly terminates the threads before the program exits. -ThreadPool::~ThreadPool() { +void ThreadPool::exit() { for (size_t i = 0; i < threads.size(); i++) delete threads[i]; diff --git a/src/thread.h b/src/thread.h index 6a929a98..38a29e8d 100644 --- a/src/thread.h +++ b/src/thread.h @@ -130,8 +130,8 @@ public: class ThreadPool { public: - void init(); // No c'tor, Threads object is global and engine shall be fully initialized - ~ThreadPool(); + void init(); // No c'tor and d'tor, threads rely on globals that should + void exit(); // be initialized and valid during the whole thread lifetime. Thread& operator[](size_t id) { return *threads[id]; } bool use_sleeping_threads() const { return useSleepingThreads; } -- 2.39.2