Emacs uses 100% cpu time

[Tassilo Horn]

>From time to time emacs starts utilizing 100% of cpu time. Sometimes it falls
back to normal usage for some seconds, but it always catches up again.

Emacs stays responsible and the only indication is that my fan is running all
the time, thus I'm not sure since when I have this problem. And I don't find a
way to reproduce the bug. The only thing I would say is that it subjectively
happens earlier, if network apps like gnus and circe are running.

I ran emacs from gdb and got this backtrace:

,----
| Program received signal SIGTSTP, Stopped (user).
| 0x08145f5d in Fgarbage_collect ()
| (gdb) bt
| #0  0x08145f5d in Fgarbage_collect ()
| #1  0x0815a11d in Ffuncall ()
| #2  0x08184baa in Fbyte_code ()
| #3  0x081598d8 in Feval ()
| #4  0x08158f1c in internal_catch ()
| #5  0x08183e2f in Fbyte_code ()
| #6  0x08159e24 in funcall_lambda ()
| #7  0x0815a23b in Ffuncall ()
| #8  0x08184baa in Fbyte_code ()
| #9  0x081598d8 in Feval ()
| #10 0x0815bf11 in internal_lisp_condition_case ()
| #11 0x08183ea9 in Fbyte_code ()
| #12 0x08159e24 in funcall_lambda ()
| #13 0x0815a23b in Ffuncall ()
| #14 0x0815bb1e in Fapply ()
| #15 0x0815a553 in Ffuncall ()
| #16 0x08184baa in Fbyte_code ()
| #17 0x081598d8 in Feval ()
| #18 0x0815bf11 in internal_lisp_condition_case ()
| #19 0x08183ea9 in Fbyte_code ()
| #20 0x08159e24 in funcall_lambda ()
| #21 0x0815a23b in Ffuncall ()
| #22 0x0815b6e9 in call1 ()
| #23 0x080fb7f7 in timer_check ()
| #24 0x0818b2e8 in wait_reading_process_output ()
| ---Type <return> to continue, or q <return> to quit---
| #25 0x08056488 in sit_for ()
| #26 0x080ff846 in read_char ()
| #27 0x081016e2 in read_key_sequence ()
| #28 0x08103195 in command_loop_1 ()
| #29 0x08158e5b in internal_condition_case ()
| #30 0x080fce2e in command_loop_2 ()
| #31 0x08158f1c in internal_catch ()
| #32 0x080fd89e in command_loop ()
| #33 0x080fdc28 in recursive_edit_1 ()
| #34 0x080fdd16 in Frecursive_edit ()
| #35 0x080f3dd2 in main ()
| (gdb) continue
| Continuing.
`----

Two interesting observation: 

- When emacs uses 100% and I press `M-x' and the mini buffer is focused
  it instantly uses a normal cpu percentage again. After the mini buffer
  activity finished it starts going crazy again.

  But when I press `M-x' and jump back to my editing buffer with `C-x o'
  it works fine, too, e.g. no high cpu utilization.

- Whenever I provide keyboard input to emacs the cpu usage goes down,
  too.

In GNU Emacs 22.0.50.1 (i686-pc-linux-gnu, GTK+ Version 2.8.20)
 of 2006-09-29 on baldur
X server distributor `The X.Org Foundation', version 11.0.70101000
configured using `configure '--prefix=/usr' '--host=i686-pc-linux-gnu' 
'--mandir=/usr/share/man' '--infodir=/usr/share/info' '--datadir=/usr/share' 
'--sysconfdir=/etc' '--localstatedir=/var/lib' 
'--program-suffix=.emacs-22.0.50' '--without-carbon' '--with-x' '--with-xpm' 
'--with-toolkit-scroll-bars' '--with-jpeg' '--with-tiff' '--with-gif' 
'--with-png' '--with-x-toolkit=gtk' '--build=i686-pc-linux-gnu' 'CFLAGS=-O2' 
'build_alias=i686-pc-linux-gnu' 'host_alias=i686-pc-linux-gnu''

Important settings:
  value of $LC_ALL: de_DE.utf8
  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: de_DE.utf8
  locale-coding-system: utf-8
  default-enable-multibyte-characters: t

Major mode: Emacs-Lisp

Minor modes in effect:
  shell-dirtrack-mode: t
  eldoc-mode: t
  tracking-mode: t
  recentf-mode: t
  desktop-save-mode: t
  show-paren-mode: t
  semantic-idle-scheduler-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t
  abbrev-mode: t

Recent input:
<up> <up> <up> <up> <up> <up> <up> <up> <up> <up> <up> 
<up> <up> <up> <up> <up> <up> <up> <up> <up> <up> <up> 
<up> <up> <up> <up> <up> <up> <up> <up> <up> <up> <up> 
<up> <up> <up> <up> <up> <up> <up> <up> <up> <up> <up> 
<up> <up> <up> <up> <up> <up> <up> <up> <up> <up> C-x 
b C-g <down-mouse-1> <mouse-movement> <mouse-1> C-x 
C-s C-g C-g C-g M-x e m <backspace> <backspace> b u 
g <tab> <backspace> <backspace> <backspace> s u b <tab> 
<backspace> <tab> <backspace> <backspace> e m a <tab> 
C-g M-x r e p <tab> o <tab> r <tab> <return>

Recent messages:
Wrote /home/heimdall/uni/repos/heimdall-uni/programs/elisp/th-abbrev.el
Loading /home/heimdall/uni/repos/heimdall-uni/programs/elisp/th-abbrev.el 
(source)...done
th-abbrev.el reloaded.
Quit
(No changes need to be saved)
Quit [3 times]
Making completion list... [2 times]
Quit
Making completion list... [2 times]
Loading emacsbug...done