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

From: Eli Zaretskii <[email-masked]>
Date: Thu, 23 Jan 2025 22:00:31 +0200

> From: Len Trigg <[email-masked]>
> Date: Fri, 24 Jan 2025 08:31:10 +1300
> Cc: Eli Zaretskii <[email-masked]>, [email-masked]
> 
> On Fri, 24 Jan 2025 at 06:34, Gerd Möllmann <[email-masked]> wrote:
> 
>  Eli Zaretskii <[email-masked]> writes:
> 
>  > What is the value of z_order?
> 
>  Len, can you please print
> 
>    p root->visible
> 
> (gdb) p root->visible
> $1 = 0
> (gdb) p z_order
> $2 = (Lisp_Object) 0x0

So the crash is because we don't verify z_order is a cons cell before
we take its cdr.