Prevent crashes due to redisplay while realizing the default face

* src/xfaces.c (Finternal_merge_in_global_face)
(realize_default_face): Prevent redisplay while the default face
is being realized.  (Bug#71176)

2 files changed, 18 insertions, 2 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index 7a00b297d61..47675fcc80a 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -13377,8 +13377,10 @@ echo_area_display (bool update_frame_p)
   w = XWINDOW (mini_window);
   f = XFRAME (WINDOW_FRAME (w));
 
-  /* Don't display if frame is invisible or not yet initialized.  */
-  if (!FRAME_REDISPLAY_P (f) || !f->glyphs_initialized_p)
+  /* Don't display if frame is invisible or not yet initialized or
+     if redisplay is inhibited.  */
+  if (!FRAME_REDISPLAY_P (f) || !f->glyphs_initialized_p
+      || !NILP (Vinhibit_redisplay))
     return;
 
 #ifdef HAVE_WINDOW_SYSTEM
diff --git a/src/xfaces.c b/src/xfaces.c
index 5192b22ce0a..258fbc52e64 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -4246,6 +4246,12 @@ Default face attributes override any local face attributes.  */)
       /* This can be NULL (e.g., in batch mode).  */
       if (oldface)
         {
+          /* In some cases, realize_face below can call Lisp, which could
+             trigger redisplay.  But we are in the process of realizing
+             the default face, and therefore are not ready to do display.  */
+          specpdl_ref count = SPECPDL_INDEX ();
+          specbind (Qinhibit_redisplay, Qt);
+
           /* Ensure that the face vector is fully specified by merging
              the previously-cached vector.  */
           memcpy (attrs, oldface->lface, sizeof attrs);
@@ -4291,6 +4297,8 @@ Default face attributes override any local face attributes.  */)
                               gvec[LFACE_BACKGROUND_INDEX]);
               Fmodify_frame_parameters (frame, arg);
             }
+
+          unbind_to (count, Qnil);
         }
     }
 
@@ -5959,7 +5967,13 @@ realize_default_face (struct frame *f)
   eassert (lface_fully_specified_p (XVECTOR (lface)->contents));
   check_lface (lface);
   memcpy (attrs, xvector_contents (lface), sizeof attrs);
+  /* In some cases, realize_face below can call Lisp, which could
+     trigger redisplay.  But we are in the process of realizing
+     the default face, and therefore are not ready to do display.  */
+  specpdl_ref count = SPECPDL_INDEX ();
+  specbind (Qinhibit_redisplay, Qt);
   struct face *face = realize_face (c, attrs, DEFAULT_FACE_ID);
+  unbind_to (count, Qnil);
 
 #ifndef HAVE_WINDOW_SYSTEM
   (void) face;