From 341b95871cdbffe8861735b507f12fab363bc469 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pedro=20J=2E=20Est=C3=A9banez?= <pedrojrulez@gmail.com>
Date: Fri, 5 May 2023 19:55:29 +0200
Subject: [PATCH] Add missing thread safety to PagedAllocator

---
 core/os/spin_lock.h              |  6 ++--
 core/templates/paged_allocator.h | 49 ++++++++++++++++++++++++++------
 2 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/core/os/spin_lock.h b/core/os/spin_lock.h
index 409154dbb56..93ea782b60e 100644
--- a/core/os/spin_lock.h
+++ b/core/os/spin_lock.h
@@ -36,15 +36,15 @@
 #include <atomic>
 
 class SpinLock {
-	std::atomic_flag locked = ATOMIC_FLAG_INIT;
+	mutable std::atomic_flag locked = ATOMIC_FLAG_INIT;
 
 public:
-	_ALWAYS_INLINE_ void lock() {
+	_ALWAYS_INLINE_ void lock() const {
 		while (locked.test_and_set(std::memory_order_acquire)) {
 			// Continue.
 		}
 	}
-	_ALWAYS_INLINE_ void unlock() {
+	_ALWAYS_INLINE_ void unlock() const {
 		locked.clear(std::memory_order_release);
 	}
 };
diff --git a/core/templates/paged_allocator.h b/core/templates/paged_allocator.h
index 1cd71ec16cd..deb29377711 100644
--- a/core/templates/paged_allocator.h
+++ b/core/templates/paged_allocator.h
@@ -99,7 +99,8 @@ public:
 		}
 	}
 
-	void reset(bool p_allow_unfreed = false) {
+private:
+	void _reset(bool p_allow_unfreed) {
 		if (!p_allow_unfreed || !std::is_trivially_destructible<T>::value) {
 			ERR_FAIL_COND(allocs_available < pages_allocated * page_size);
 		}
@@ -116,16 +117,41 @@ public:
 			allocs_available = 0;
 		}
 	}
+
+public:
+	void reset(bool p_allow_unfreed = false) {
+		if (thread_safe) {
+			spin_lock.lock();
+		}
+		_reset(p_allow_unfreed);
+		if (thread_safe) {
+			spin_lock.unlock();
+		}
+	}
+
 	bool is_configured() const {
-		return page_size > 0;
+		if (thread_safe) {
+			spin_lock.lock();
+		}
+		bool result = page_size > 0;
+		if (thread_safe) {
+			spin_lock.unlock();
+		}
+		return result;
 	}
 
 	void configure(uint32_t p_page_size) {
+		if (thread_safe) {
+			spin_lock.lock();
+		}
 		ERR_FAIL_COND(page_pool != nullptr); //sanity check
 		ERR_FAIL_COND(p_page_size == 0);
 		page_size = nearest_power_of_2_templated(p_page_size);
 		page_mask = page_size - 1;
 		page_shift = get_shift_from_power_of_2(page_size);
+		if (thread_safe) {
+			spin_lock.unlock();
+		}
 	}
 
 	// Power of 2 recommended because of alignment with OS page sizes.
@@ -135,13 +161,20 @@ public:
 	}
 
 	~PagedAllocator() {
-		if (allocs_available < pages_allocated * page_size) {
-			if (CoreGlobals::leak_reporting_enabled) {
-				ERR_FAIL_COND_MSG(allocs_available < pages_allocated * page_size, String("Pages in use exist at exit in PagedAllocator: ") + String(typeid(T).name()));
-			}
-			return;
+		if (thread_safe) {
+			spin_lock.lock();
+		}
+		bool leaked = allocs_available < pages_allocated * page_size;
+		if (leaked) {
+			if (CoreGlobals::leak_reporting_enabled) {
+				ERR_PRINT(String("Pages in use exist at exit in PagedAllocator: ") + String(typeid(T).name()));
+			}
+		} else {
+			_reset(false);
+		}
+		if (thread_safe) {
+			spin_lock.unlock();
 		}
-		reset();
 	}
 };