bug#74535: 30.0.92; partial hang, esp. keyboard events

[Eli Zaretskii <eliz@gnu.org>]

> From: Mike Kupfer <kupfer@rawbw.com>
> Date: Mon, 25 Nov 2024 11:13:00 -0800
> 
> I've been getting occasional Emacs hangs, under both Xfce and MATE.  I
> haven't seen the problem (so far) with i3.  Emacs seems to handle mouse
> events okay, e.g., it looks like point is moving in response to a mouse
> click.  And I can create new frames using emacsclient.  But keyboard
> events don't seem to be processed--there's no response to C-g, M-x,
> C-p, C-n, simple text, F10.
> 
> I tried troubleshooting the problem using strace (simple "strace -p
> <emacs_pid>"), but there's so much output I've been unable to make sense
> of it.
> 
> I don't have a reliable recipe for reproducing the problem.  It *might*
> be related to closing a frame.
> 
> I did not see this problem with 30.0.91.
> 
> My current plan for troubleshooting (the next time it happens) is to
> attach gdb, dump the last 10 items in recent_keys (using the
> instructions in etc/DEBUG), resume the process, type a few keys, go back
> into gdb, and see if recent_keys and recent_keys_index have changed.  Is
> there a better approach?

Bisecting is better.  Since you didn't have this problem with the
previous pretest (but please verify that first: it could be that the
problem started happening because of an unrelated change to your
system), you need to bisect between that and the last pretest, which
shouldn't be a lot of revisions.

Thanks.