Subject: bug#75056: 31.0.50; tty-child-frames with server / multiple clients possible hangs

From: Eli Zaretskii <[email-masked]>
Date: Thu, 23 Jan 2025 18:38:28 +0200

> From: Len Trigg <[email-masked]>
> Date: Fri, 24 Jan 2025 05:00:33 +1300
> Cc: [email-masked], [email-masked]
> 
> #0  combine_updates_for_frame (f=f@entry=0x555556ca8d58,
> inhibit_scrolling=inhibit_scrolling@entry=false) at dispnew.c:3973

The crash is here:

  for (Lisp_Object tail = XCDR (z_order); CONSP (tail); tail = XCDR (tail))
    {
      topmost_child = XFRAME (XCAR (tail));
      copy_child_glyphs (root, topmost_child);
    }

What is the value of z_order?