1 files changed, 8 insertions, 0 deletions

diff --git a/src/alloc.c b/src/alloc.c
index 22153110480..e6edea42c95 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -1587,10 +1587,18 @@ mark_object (objptr)
         if (XMARKBIT (ptr->plist)) break;
         XMARK (ptr->plist);
         mark_object ((Lisp_Object *) &ptr->value);
+        if ((unsigned int) ptr <= 4)
+          abort ();
         mark_object (&ptr->function);
+        if ((unsigned int) ptr <= 4)
+          abort ();
         mark_object (&ptr->plist);
+        if ((unsigned int) ptr <= 4)
+          abort ();
         XSETTYPE (*(Lisp_Object *) &ptr->name, Lisp_String);
         mark_object (&ptr->name);
+        if ((unsigned int) ptr <= 4)
+          abort ();
         ptr = ptr->next;
         if (ptr)
           {