diff --git a/direct/src/dcparser/dcPacker.I b/direct/src/dcparser/dcPacker.I
index 6b6ef79ee5..c9212b3302 100644
--- a/direct/src/dcparser/dcPacker.I
+++ b/direct/src/dcparser/dcPacker.I
@@ -1124,7 +1124,9 @@ operator new(size_t size) {
  */
 INLINE void DCPacker::StackElement::
 operator delete(void *ptr) {
-  StackElement *obj = (StackElement *)ptr;
-  obj->_next = _deleted_chain;
-  _deleted_chain = obj;
+  if (ptr != nullptr) {
+    StackElement *obj = (StackElement *)ptr;
+    obj->_next = _deleted_chain;
+    _deleted_chain = obj;
+  }
 }
diff --git a/direct/src/distributed/ServerRepository.py b/direct/src/distributed/ServerRepository.py
index 966d22923b..ac0f2c6856 100644
--- a/direct/src/distributed/ServerRepository.py
+++ b/direct/src/distributed/ServerRepository.py
@@ -628,7 +628,7 @@ class ServerRepository:
         del self.clientsByConnection[client.connection]
         del self.clientsByDoIdBase[client.doIdBase]
 
-        id = client.doIdBase / self.doIdRange
+        id = client.doIdBase // self.doIdRange
         self.idAllocator.free(id)
 
         self.qcr.removeConnection(client.connection)
@@ -689,7 +689,7 @@ class ServerRepository:
     def clientHardDisconnectTask(self, task):
         """ client did not tell us he was leaving but we lost connection to
         him, so we need to update our data and tell others """
-        for client in self.clientsByConnection.values():
+        for client in list(self.clientsByConnection.values()):
             if not self.qcr.isConnectionOk(client.connection):
                 self.handleClientDisconnect(client)
         return Task.cont
diff --git a/dtool/src/dtoolbase/deletedChain.h b/dtool/src/dtoolbase/deletedChain.h
index 1915223450..a72bc85f96 100644
--- a/dtool/src/dtoolbase/deletedChain.h
+++ b/dtool/src/dtoolbase/deletedChain.h
@@ -85,7 +85,9 @@ public:
     return ptr;                                              \
   }                                                          \
   inline void operator delete(void *ptr) {                   \
-    StaticDeletedChain< Type >::deallocate((Type *)ptr, get_type_handle(Type)); \
+    if (ptr != nullptr) {                                    \
+      StaticDeletedChain< Type >::deallocate((Type *)ptr, get_type_handle(Type)); \
+    }                                                        \
   }                                                          \
   inline void operator delete(void *, void *) {              \
   }                                                          \
@@ -104,7 +106,9 @@ public:
     return ptr;                                              \
   }                                                          \
   inline void operator delete(void *ptr) {                   \
-    _deleted_chain.deallocate((Type *)ptr, get_type_handle(Type)); \
+    if (ptr != nullptr) {                                    \
+      _deleted_chain.deallocate((Type *)ptr, get_type_handle(Type)); \
+    }                                                        \
   }                                                          \
   inline void operator delete(void *, void *) {              \
   }                                                          \
diff --git a/dtool/src/dtoolbase/memoryBase.h b/dtool/src/dtoolbase/memoryBase.h
index d1d9f00ca5..b82e9d1cc0 100644
--- a/dtool/src/dtoolbase/memoryBase.h
+++ b/dtool/src/dtoolbase/memoryBase.h
@@ -32,7 +32,9 @@
     return ptr;                                              \
   }                                                          \
   inline void operator delete(void *ptr) {                   \
-    PANDA_FREE_SINGLE(ptr);                                  \
+    if (ptr != nullptr) {                                    \
+      PANDA_FREE_SINGLE(ptr);                                \
+    }                                                        \
   }                                                          \
   inline void operator delete(void *, void *) {              \
   }                                                          \
@@ -44,7 +46,9 @@
     return ptr;                                              \
   }                                                          \
   inline void operator delete[](void *ptr) {                 \
-    PANDA_FREE_ARRAY(ptr);                                   \
+    if (ptr != nullptr) {                                    \
+      PANDA_FREE_ARRAY(ptr);                                 \
+    }                                                        \
   }                                                          \
   inline void operator delete[](void *, void *) {            \
   }