diff --git a/panda/src/pgraph/pandaNode.I b/panda/src/pgraph/pandaNode.I
index 1695fe5197..f00b6d00aa 100644
--- a/panda/src/pgraph/pandaNode.I
+++ b/panda/src/pgraph/pandaNode.I
@@ -848,36 +848,34 @@ verify_child_no_cycles(PandaNode *child_node) {
 }
 
 ////////////////////////////////////////////////////////////////////
-//     Function: PandaNode::set_dirty_prev_transform
+//     Function: PandaNode::do_set_dirty_prev_transform
 //       Access: Private
 //  Description: Sets the dirty_prev_transform flag, and adds the node
-//               to the _dirty_prev_transforms chain.
+//               to the _dirty_prev_transforms chain.  Assumes
+//               _dirty_prev_transforms._lock is already held.
 ////////////////////////////////////////////////////////////////////
 INLINE void PandaNode::
-set_dirty_prev_transform() {
+do_set_dirty_prev_transform() {
+  nassertv(_dirty_prev_transforms._lock.debug_is_locked());
   if (!_dirty_prev_transform) {
-    LightMutexHolder holder(_dirty_prev_transforms._lock);
-    if (!_dirty_prev_transform) {
-      LinkedListNode::insert_before(&_dirty_prev_transforms);
-      _dirty_prev_transform = true;
-    }
+    LinkedListNode::insert_before(&_dirty_prev_transforms);
+    _dirty_prev_transform = true;
   }
 }
 
 ////////////////////////////////////////////////////////////////////
-//     Function: PandaNode::clear_dirty_prev_transform
+//     Function: PandaNode::do_clear_dirty_prev_transform
 //       Access: Private
 //  Description: Clears the dirty_prev_transform flag, and removes the node
-//               from the _dirty_prev_transforms chain.
+//               from the _dirty_prev_transforms chain.  Assumes
+//               _dirty_prev_transforms._lock is already held.
 ////////////////////////////////////////////////////////////////////
 INLINE void PandaNode::
-clear_dirty_prev_transform() {
+do_clear_dirty_prev_transform() {
+  nassertv(_dirty_prev_transforms._lock.debug_is_locked());
   if (_dirty_prev_transform) {
-    LightMutexHolder holder(_dirty_prev_transforms._lock);
-    if (_dirty_prev_transform) {
-      LinkedListNode::remove_from_list();
-      _dirty_prev_transform = false;
-    }
+    LinkedListNode::remove_from_list();
+    _dirty_prev_transform = false;
   }
 }
 
diff --git a/panda/src/pgraph/pandaNode.cxx b/panda/src/pgraph/pandaNode.cxx
index 53e46482fe..70360c802c 100644
--- a/panda/src/pgraph/pandaNode.cxx
+++ b/panda/src/pgraph/pandaNode.cxx
@@ -38,7 +38,7 @@ TypeHandle PandaNode::BamReaderAuxDataDown::_type_handle;
 
 PandaNode::SceneRootFunc *PandaNode::_scene_root_func;
 
-PandaNodeChain PandaNode::_dirty_prev_transforms;
+PandaNodeChain PandaNode::_dirty_prev_transforms("_dirty_prev_transforms");
 DrawMask PandaNode::_overall_bit = DrawMask::bit(31);
 
 PStatCollector PandaNode::_reset_prev_pcollector("App:Collisions:Reset");
@@ -108,7 +108,12 @@ PandaNode::
     pgraph_cat.debug()
       << "Destructing " << (void *)this << ", " << get_name() << "\n";
   }
-  clear_dirty_prev_transform();
+
+  if (_dirty_prev_transform) {
+    // Need to have this held before we grab any other locks.
+    LightMutexHolder holder(_dirty_prev_transforms._lock);
+    do_clear_dirty_prev_transform();
+  }
 
   // We shouldn't have any parents left by the time we destruct, or
   // there's a refcount fault somewhere.
@@ -155,6 +160,9 @@ PandaNode(const PandaNode &copy) :
   _unexpected_change_flags = 0;
 #endif // !NDEBUG
 
+  // Need to have this held before we grab any other locks.
+  LightMutexHolder holder(_dirty_prev_transforms._lock);
+
   // Copy the other node's state.
   {
     CDReader copy_cdata(copy._cycler);
@@ -163,7 +171,7 @@ PandaNode(const PandaNode &copy) :
     cdata->_transform = copy_cdata->_transform;
     cdata->_prev_transform = copy_cdata->_prev_transform;
     if (cdata->_transform != cdata->_prev_transform) {
-      set_dirty_prev_transform();
+      do_set_dirty_prev_transform();
     }
 
     cdata->_effects = copy_cdata->_effects;
@@ -1336,6 +1344,9 @@ set_effects(const RenderEffects *effects, Thread *current_thread) {
 ////////////////////////////////////////////////////////////////////
 void PandaNode::
 set_transform(const TransformState *transform, Thread *current_thread) {
+  // Need to have this held before we grab any other locks.
+  LightMutexHolder holder(_dirty_prev_transforms._lock);
+
   // Apply this operation to the current stage as well as to all
   // upstream stages.
   bool any_changed = false;
@@ -1348,7 +1359,7 @@ set_transform(const TransformState *transform, Thread *current_thread) {
 
       if (pipeline_stage == 0) {
         if (cdata->_transform != cdata->_prev_transform) {
-          set_dirty_prev_transform();
+          do_set_dirty_prev_transform();
         }
       }
     }
@@ -1372,6 +1383,9 @@ set_transform(const TransformState *transform, Thread *current_thread) {
 ////////////////////////////////////////////////////////////////////
 void PandaNode::
 set_prev_transform(const TransformState *transform, Thread *current_thread) {
+  // Need to have this held before we grab any other locks.
+  LightMutexHolder holder(_dirty_prev_transforms._lock);
+
   // Apply this operation to the current stage as well as to all
   // upstream stages.
   OPEN_ITERATE_CURRENT_AND_UPSTREAM(_cycler, current_thread) {
@@ -1379,9 +1393,9 @@ set_prev_transform(const TransformState *transform, Thread *current_thread) {
     cdata->_prev_transform = transform;
     if (pipeline_stage == 0) {
       if (cdata->_transform != cdata->_prev_transform) {
-        set_dirty_prev_transform();
+        do_set_dirty_prev_transform();
       } else {
-        clear_dirty_prev_transform();
+        do_clear_dirty_prev_transform();
       }
     }
   }
@@ -1399,9 +1413,12 @@ set_prev_transform(const TransformState *transform, Thread *current_thread) {
 ////////////////////////////////////////////////////////////////////
 void PandaNode::
 reset_prev_transform(Thread *current_thread) {
+  // Need to have this held before we grab any other locks.
+  LightMutexHolder holder(_dirty_prev_transforms._lock);
+  do_clear_dirty_prev_transform();
+
   // Apply this operation to the current stage as well as to all
   // upstream stages.
-  clear_dirty_prev_transform();
 
   OPEN_ITERATE_CURRENT_AND_UPSTREAM(_cycler, current_thread) {
     CDStageWriter cdata(_cycler, pipeline_stage, current_thread);
@@ -1800,6 +1817,9 @@ copy_all_properties(PandaNode *other) {
     return;
   }
 
+  // Need to have this held before we grab any other locks.
+  LightMutexHolder holder(_dirty_prev_transforms._lock);
+
   bool any_transform_changed = false;
   bool any_state_changed = false;
   bool any_draw_mask_changed = false;
@@ -1871,7 +1891,7 @@ copy_all_properties(PandaNode *other) {
 
     if (pipeline_stage == 0) {
       if (cdataw->_transform != cdataw->_prev_transform) {
-        set_dirty_prev_transform();
+        do_set_dirty_prev_transform();
       }
     }
   }
diff --git a/panda/src/pgraph/pandaNode.h b/panda/src/pgraph/pandaNode.h
index 186d99aba3..f2c0a19e0a 100644
--- a/panda/src/pgraph/pandaNode.h
+++ b/panda/src/pgraph/pandaNode.h
@@ -416,8 +416,8 @@ private:
   void fix_path_lengths(int pipeline_stage, Thread *current_thread);
   void r_list_descendants(ostream &out, int indent_level) const;
   
-  INLINE void set_dirty_prev_transform();
-  INLINE void clear_dirty_prev_transform();
+  INLINE void do_set_dirty_prev_transform();
+  INLINE void do_clear_dirty_prev_transform();
 
 public:
   // This must be declared public so that VC6 will allow the nested
diff --git a/panda/src/pgraph/pandaNodeChain.I b/panda/src/pgraph/pandaNodeChain.I
index 5e2296d137..e3b9b7f931 100644
--- a/panda/src/pgraph/pandaNodeChain.I
+++ b/panda/src/pgraph/pandaNodeChain.I
@@ -19,8 +19,9 @@
 //  Description:
 ////////////////////////////////////////////////////////////////////
 INLINE PandaNodeChain::
-PandaNodeChain() :
-  LinkedListNode(true)  // This object is the root of a list of PandaNodes.
+PandaNodeChain(const char *lock_name) :
+  LinkedListNode(true),  // This object is the root of a list of PandaNodes.
+ _lock(lock_name)
 {
 }
 
diff --git a/panda/src/pgraph/pandaNodeChain.h b/panda/src/pgraph/pandaNodeChain.h
index de554b6bcf..2bc2863824 100644
--- a/panda/src/pgraph/pandaNodeChain.h
+++ b/panda/src/pgraph/pandaNodeChain.h
@@ -30,7 +30,7 @@ class PandaNode;
 ////////////////////////////////////////////////////////////////////
 class EXPCL_PANDA_PGRAPH PandaNodeChain : private LinkedListNode {
 public:
-  INLINE PandaNodeChain();
+  INLINE PandaNodeChain(const char *lock_name);
   INLINE ~PandaNodeChain();
 
   LightMutex _lock;