diff --git a/lisp/progmodes/cc-mode.el b/lisp/progmodes/cc-mode.el
index 8cbb4e86123..5283cfea6eb 100644
--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -1487,6 +1487,7 @@ Note that this is a strict tail, so won't match, e.g. \"0x....\".")
   ;; lock context (etc.) fontification.
   (goto-char pos)
   (let ((lit-start (c-literal-start))
+	old-pos
 	(new-pos pos)
 	capture-opener
 	bod-lim bo-decl)
@@ -1509,12 +1510,14 @@ Note that this is a strict tail, so won't match, e.g. \"0x....\".")
     (while
 	;; Go to a less nested declaration each time round this loop.
 	(and
+	 (setq old-pos (point))
 	 (c-syntactic-skip-backward "^;{}" bod-lim t)
 	 (> (point) bod-lim)
 	 (progn (c-forward-syntactic-ws)
 		;; Have we got stuck in a comment at EOB?
 		(not (and (eobp)
 			  (c-literal-start))))
+	 (< (point) old-pos)
 	 (progn (setq bo-decl (point))
 		(or (not (looking-at c-protection-key))
 		    (c-forward-keyword-clause 1)))