Avoid crashing due to closing of font whose driver pointer is NULL.

 src/alloc.c (cleanup_vector): Don't call the font driver's 'close'
 method if the 'driver' pointer is NULL.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/alloc.c b/src/alloc.c
index aeda42637cd..1cf0f3cc1d2 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -2877,7 +2877,12 @@ cleanup_vector (struct Lisp_Vector *vector)
   if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_FONT)
       && ((vector->header.size & PSEUDOVECTOR_SIZE_MASK)
           == FONT_OBJECT_MAX))
-    ((struct font *) vector)->driver->close ((struct font *) vector);
+    {
+      struct font *fnt = (struct font *) vector;
+
+      if (fnt->driver)
+        fnt->driver->close ((struct font *) vector);
+    }
 }
 
 /* Reclaim space used by unmarked vectors.  */