From f0a7d1faaae4e100cba45a6c8c0787f18feabe47 Mon Sep 17 00:00:00 2001
From: David Capello <david@igarastudio.com>
Date: Tue, 19 Apr 2022 17:09:49 -0300
Subject: [PATCH] Fix data race loading next thumbnail without locking the item

This was detected with -fsanitize=thread
---
 src/app/thumbnail_generator.cpp | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/app/thumbnail_generator.cpp b/src/app/thumbnail_generator.cpp
index d4677d59a..ded732746 100644
--- a/src/app/thumbnail_generator.cpp
+++ b/src/app/thumbnail_generator.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2020  Igara Studio S.A.
+// Copyright (C) 2019-2022  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -199,8 +199,14 @@ private:
 
   void loadBgThread() {
     while (!m_queue.empty()) {
-      while (m_queue.try_pop(m_item)) {
-        loadItem();
+      bool success = true;
+      while (success) {
+        {
+          base::scoped_lock lock(m_mutex); // To access m_item
+          success = m_queue.try_pop(m_item);
+        }
+        if (success)
+          loadItem();
       }
       base::this_thread::yield();
     }