diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 70ae97614d..954fb5317a 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2011-06-20  Tom Tromey  <tromey@redhat.com>
+
+	* symtab.c (lookup_language_this): End loop if block is NULL.
+
 2011-06-17  Tom Tromey  <tromey@redhat.com>
 
 	* valops.c (value_of_this): Use lookup_language_this.
diff --git a/gdb/symtab.c b/gdb/symtab.c
index d627636ae1..13234f236d 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -1100,7 +1100,7 @@ lookup_language_this (const struct language_defn *lang,
   if (lang->la_name_of_this == NULL || block == NULL)
     return NULL;
 
-  while (1)
+  while (block)
     {
       struct symbol *sym;
 
@@ -1108,9 +1108,11 @@ lookup_language_this (const struct language_defn *lang,
       if (sym != NULL)
 	return sym;
       if (BLOCK_FUNCTION (block))
-	return NULL;
+	break;
       block = BLOCK_SUPERBLOCK (block);
     }
+
+  return NULL;
 }
 
 /* Behave like lookup_symbol except that NAME is the natural name