Protect accesses to the Render cache

It seems Qt6 QHash implementation might rehash on lookups which leads
to data races in case of concurrent lookups

Change-Id: I9fff2c8303fdd5908acc27d6d98fc963876d65cc
Reviewed-by: Mike Krus <mike.krus@kdab.com>
(cherry picked from commit 308fd2598eab048de45df274c408fb2d43fb3bcf)

1 files changed, 4 insertions, 1 deletions

diff --git a/src/plugins/renderers/opengl/renderer/renderviewbuilder.cpp b/src/plugins/renderers/opengl/renderer/renderviewbuilder.cpp
index e971c3f3c..7dad70483 100644
--- a/src/plugins/renderers/opengl/renderer/renderviewbuilder.cpp
+++ b/src/plugins/renderers/opengl/renderer/renderviewbuilder.cpp
@@ -79,6 +79,7 @@ public:
 
         // Rebuild RenderCommands for all entities in RV (ignoring filtering)
         RendererCache *cache = m_renderer->cache();
+        QMutexLocker lock(cache->mutex());
 
         Q_ASSERT(cache->leafNodeCache.contains(m_leafNode));
         // The cache leaf should already have been created so we don't need to protect the access
@@ -284,6 +285,7 @@ public:
             ///////// CACHE LOCKED ////////////
             // Retrieve Data from Cache
             RendererCache *cache = m_renderer->cache();
+            QMutexLocker lock(cache->mutex());
             Q_ASSERT(cache->leafNodeCache.contains(m_leafNode));
 
             // We don't need to protect the cache access as
@@ -506,6 +508,7 @@ public:
 
     void operator()()
     {
+        QMutexLocker lock(m_renderer->cache()->mutex());
         Q_ASSERT(m_renderer->cache()->leafNodeCache.contains(m_leafNode));
         // The cache leaf should already have been created so we don't need to protect the access
         RendererCache::LeafNodeData &dataCacheForLeaf = m_renderer->cache()->leafNodeCache[m_leafNode];
@@ -535,7 +538,7 @@ public:
     {
         // The cache leaf was created by SyncRenderViewPostInitialization on which we depend
         // so we don't need to protect the access
-
+        QMutexLocker lock(m_renderer->cache()->mutex());
         RendererCache::LeafNodeData &dataCacheForLeaf = m_renderer->cache()->leafNodeCache[m_leafNode];
         dataCacheForLeaf.materialParameterGatherer.clear();