From 1121f5a8b93016992e122150ea3c867204ab407b Mon Sep 17 00:00:00 2001
From: johannst <johannes.stoelp@gmail.com>
Date: Thu, 22 Oct 2020 20:13:38 +0200
Subject: fix memory leak when destroying Thread objects

---
 lib/executor.cc |  2 +-
 lib/thread.cc   | 16 ++++++++++++----
 lib/thread.h    | 10 +++++++---
 3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/lib/executor.cc b/lib/executor.cc
index bfc268a..52bdf01 100644
--- a/lib/executor.cc
+++ b/lib/executor.cc
@@ -27,6 +27,6 @@ namespace nMatcha {
     }
 
     void Executor::yield_to(const Thread* t) {
-        ::yield(t->mStackPtr, &mStackPtr);
+        ::yield(t->mStack.mPtr, &mStackPtr);
     }
 }  // namespace nMatcha
diff --git a/lib/thread.cc b/lib/thread.cc
index 424041d..304091d 100644
--- a/lib/thread.cc
+++ b/lib/thread.cc
@@ -18,7 +18,7 @@ namespace {
 }  // namespace
 
 namespace nMatcha {
-    Thread::Thread() : mStackPtr(nullptr), mFinished(false), mExecutor(nullptr) {
+    Thread::Thread() : mStack{}, mFinished(false), mExecutor(nullptr) {
         const long PAGE_SIZE = get_pagesize();
         const long STACK_SIZE = 8 * PAGE_SIZE;
 
@@ -35,10 +35,18 @@ namespace nMatcha {
         assert(ret == 0);
 
         // Adjust stack pointer, as stack grows downwards.
-        mStackPtr = static_cast<uint8_t*>(stack) + STACK_SIZE;
+        mStack.mPtr = static_cast<uint8_t*>(stack) + STACK_SIZE;
+        mStack.mBottom = stack;
+        mStack.mSize= STACK_SIZE;
+
 
         // Arch specific stack initialization.
-        mStackPtr = init_stack(mStackPtr, Thread::entry, static_cast<void*>(this));
+        mStack.mPtr = init_stack(mStack.mPtr, Thread::entry, static_cast<void*>(this));
+    }
+
+    Thread::~Thread() {
+            int ret = ::munmap(mStack.mBottom, mStack.mSize);
+            assert(ret == 0);
     }
 
     bool Thread::isFinished() const {
@@ -60,7 +68,7 @@ namespace nMatcha {
 
     void Thread::yield() {
         assert(mExecutor);
-        ::yield(mExecutor->getStackPtr(), &mStackPtr);
+        ::yield(mExecutor->getStackPtr(), &mStack.mPtr);
     }
 
     std::unique_ptr<Thread> FnThread::make(UserFn f) {
diff --git a/lib/thread.h b/lib/thread.h
index 3dfa457..4cae2e1 100644
--- a/lib/thread.h
+++ b/lib/thread.h
@@ -33,7 +33,7 @@ namespace nMatcha {
         Thread(const Thread&) = delete;
         Thread& operator=(const Thread&) = delete;
         Thread();
-        virtual ~Thread() {}
+        virtual ~Thread();
 
         bool isFinished() const;
 
@@ -42,9 +42,13 @@ namespace nMatcha {
 
       private:
         virtual void threadFn() = 0;
-
         static void entry(void* ctx);
-        void* mStackPtr;
+
+        struct Stack {
+            void* mBottom;
+            size_t mSize;
+            void* mPtr;
+        } mStack;
         bool mFinished;
 
         friend struct Executor;
-- 
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