Subject: bug#34260: 27.0.50; Emacs randomly hangs during redisplay

From: John Shahid <[email-masked]>
Date: Thu, 31 Jan 2019 09:07:26 -0500

martin rudalics <[email-masked]> writes:

>> Let me know how I can debug this issue further.  Would the display
>> engine trace help in this case ?  Emacs doesn't enter an infinite
>> recursion but from the CPU usage it is entering some sort of infinite
>> loop, but I can't figure out why.
>
> Please tell me if the following hold when the hang occurs:
>
> (1) You have at least two frames open.

Yes.  EXWM creates a frame per monitor.  I have two monitors which is
equivalent to two frames.  I verified that by running `(frame-list)'
which gave me the following `(#<frame *Minibuf-1* 0x915df20> #<frame
*eshell* 0x1408c30>)'.

> (2) You run an externl process (likely shell) in a non-selected frame.

Very likely.  I didn't what to look for when this happened, but I almost
always have an eshell/ansi-term window open.

> (3) The minibuffer window of the selected frame is or should be enlarged.

I am not sure.  In the stacktraces I looked at there was always a call
to `message', but I'm not sure what are the args to it.  Due to the
nature of my setup (i.e. using EXWM/Emacs as the window manager), when
this happen it is little hard to debug from inside Emacs and I have to
use gdb.  I am not sure how to get the args from gdb.

JS