bug#10669: 24.0.93; Emacs daemon high CPU load

[Michael Welsh Duggan]

In certain circumstances, emacs running in daemon mode ends up in a high
CPU state, and fills the .xsession-errors log with large numbers of
"Back to top level." messages.  I am using a freshly bootstrapped bzr
trunk checkout of emacs from 2012.01.29.

Here follows the minimal set of steps I was able to determine that
recreates the problem.  Small deviations from this (such as not using
emacsclient) did not trigger the problem.  I am running Gnome 3 and the
gnome-shell, but have seen (although not tested in detail) this same
problem in a Gnome 2 desktop session.

In a Gnome desktop session:

1) Create a .emacs file containing the following single line:

   (server-start)

2) Start emacs using the following incantation:

   emacsclient -a "" -c -n

3) Log out of the desktop session.

4) Log in.

5) Run top.  See that emacs is taking up most of the CPU.

I have been able to attach gdb to the runaway process, but have as yet
been unable to determine what it is doing.  If others are unable to
recreate the problem, I am happy to try debugging on this end, with a
little guidance.



In GNU Emacs 24.0.93.1 (i686-pc-linux-gnu, X toolkit)
 of 2012-01-29 on maru
Windowing system distributor `The X.Org Foundation', version 11.0.11103901
Configured using:
 `configure '--enable-asserts' 'CFLAGS=-ggdb3 -O0'
 '--without-toolkit-scroll-bars' '--enable-maintainer-mode'
 '--with-x-toolkit=lucid''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.utf8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

-- 
Michael Welsh Duggan
(md5i@md5i.com)