* lisp/emacs-lisp/edebug.el (edebug-instrument-function): Check a marker is

still valid before using it.

2 files changed, 4 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 28f0b8d0bef..dd33dda4382 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,5 +1,8 @@
 2011-02-10  Stefan Monnier  <monnier@iro.umontreal.ca>
 
+        * emacs-lisp/edebug.el (edebug-instrument-function): Check a marker is
+        still valid before using it.
+
         * progmodes/grep.el (grep-mode-font-lock-keywords): Adjust to
         `message' -> `compilation-message' rename (bug#8004).
 
diff --git a/lisp/emacs-lisp/edebug.el b/lisp/emacs-lisp/edebug.el
index f281521841c..70a7983dbea 100644
--- a/lisp/emacs-lisp/edebug.el
+++ b/lisp/emacs-lisp/edebug.el
@@ -3394,7 +3394,7 @@ go to the end of the last sexp, or if that is the same point, then step."
   ;; Return the function symbol, or nil if not instrumented.
   (let ((func-marker (get func 'edebug)))
     (cond
-     ((markerp func-marker)
+     ((and (markerp func-marker) (marker-buffer func-marker))
       ;; It is uninstrumented, so instrument it.
       (with-current-buffer (marker-buffer func-marker)
         (goto-char func-marker)