1 files changed, 2 insertions, 0 deletions

diff --git a/src/buffer.c b/src/buffer.c
index f8d5bdc76fe..09166b17cfb 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1615,6 +1615,8 @@ the current buffer's major mode.  */)
   int count;
   Lisp_Object function;
 
+  CHECK_BUFFER (buffer);
+
   if (STRINGP (XBUFFER (buffer)->name)
       && strcmp (SDATA (XBUFFER (buffer)->name), "*scratch*") == 0)
     function = find_symbol_value (intern ("initial-major-mode"));