Done. The bug is reported as bug ID 25172

Regards,
Elias

On 12 December 2016 at 00:16, Eli Zaretskii <eliz@gnu.org> wrote:
> From: Simon Leinen <simon.leinen@gmail.com>
> Date: Sun, 11 Dec 2016 10:08:41 +0100
> Cc: emacs-devel <emacs-devel@gnu.org>
>
> On Sun, Dec 11, 2016 at 8:12 AM, Elias Mårtenson <lokedhs@gmail.com> wrote:
> >     (make-thread (lambda ()
> >         (sit-for 5)
> >         (with-current-buffer "z"
> >             (insert "foo"))))
>
> Ouch! I'm more or less able to reproduce the problem: When I call this
> twice (the second time with the "z" buffer open in a separate frame),
> this ends badly.  Emacs didn't crash, but became unresponsive.  None
> of kill{, -1, -15} helped, only kill -9 killed it.  Unfortunately I'm
> running under Mac OS X (GNU Emacs 26.0.50.3
> (x86_64-apple-darwin15.6.0, X toolkit, Xaw3d scroll bars) of
> 2016-12-10 - sorry, that's all my employer tolerates), so I'm not
> really able to help debug this.  If help is needed I can try under
> GNU/Linux in a VM.

Thanks, but please report these as bugs to the bug tracker.