(Fprimitive_undo): GCPRO next and list.

Check argument type before calling XINT.

1 files changed, 9 insertions, 2 deletions

diff --git a/src/undo.c b/src/undo.c
index 4733694ff31..fef2698c759 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -335,8 +335,10 @@ Return what remains of the list.")
   (n, list)
      Lisp_Object n, list;
 {
+  struct gcpro gcpro1, gcpro2;
+  Lisp_Object next;
   int count = specpdl_ptr - specpdl;
-  register int arg = XINT (n);
+  register int arg;
 #if 0  /* This is a good feature, but would make undo-start
           unable to do what is expected.  */
   Lisp_Object tem;
@@ -348,6 +350,11 @@ Return what remains of the list.")
     list = Fcdr (list);
 #endif
 
+  CHECK_NUMBER (n, 0);
+  arg = XINT (n);
+  next = Qnil;
+  GCPRO2 (next, list);
+
   /* Don't let read-only properties interfere with undo.  */
   if (NILP (current_buffer->read_only))
     specbind (Qinhibit_read_only, Qt);
@@ -356,7 +363,6 @@ Return what remains of the list.")
     {
       while (1)
         {
-          Lisp_Object next;
           next = Fcar (list);
           list = Fcdr (list);
           /* Exit inner loop at undo boundary.  */
@@ -455,6 +461,7 @@ Return what remains of the list.")
       arg--;
     }
 
+  UNGCPRO;
   return unbind_to (count, list);
 }