Merge branch 'temp-openxr-ghostxr' into temp-openxr-blenderside

1 files changed, 12 insertions, 0 deletions

diff --git a/source/blender/depsgraph/intern/builder/deg_builder_nodes.cc b/source/blender/depsgraph/intern/builder/deg_builder_nodes.cc
index 01d84f6b5d8..c512300200e 100644
--- a/source/blender/depsgraph/intern/builder/deg_builder_nodes.cc
+++ b/source/blender/depsgraph/intern/builder/deg_builder_nodes.cc
@@ -319,6 +319,18 @@ void DepsgraphNodeBuilder::begin_build()
    * them for new ID nodes. */
   id_info_hash_ = BLI_ghash_ptr_new("Depsgraph id hash");
   for (IDNode *id_node : graph_->id_nodes) {
+    /* It is possible that the ID does not need to have CoW version in which case id_cow is the
+     * same as id_orig. Additionally, such ID might have been removed, which makes the check
+     * for whether id_cow is expanded to access freed memory. In orderr to deal with this we
+     * check whether CoW is needed based on a scalar value which does not lead to access of
+     * possibly deleted memory.
+     * Additionally, this saves some space in the map by skipping mapping for datablocks which
+     * do not need CoW, */
+    if (!deg_copy_on_write_is_needed(id_node->id_type)) {
+      id_node->id_cow = nullptr;
+      continue;
+    }
+
     IDInfo *id_info = (IDInfo *)MEM_mallocN(sizeof(IDInfo), "depsgraph id info");
     if (deg_copy_on_write_is_expanded(id_node->id_cow) && id_node->id_orig != id_node->id_cow) {
       id_info->id_cow = id_node->id_cow;