Bug 114146 – X server temporarily attacks the CPU with DoS

• Product: Gentoo Linux
• Status: RESOLVED NEEDINFO

[Description Clock 2005-12-01 06:46:43 UTC]

If I run some program in xterm and break it, with probability about 5% the X
server starts consuming 100% CPU for about 20 seconds, the systems becomes
very unresponsive, and xterm stops redrawing the window. Then xterm redraws the
window and the system gets back to normal again.

To see which process does the DoS I used top (which is very hard to start quickly
enough under the condition). It happened to me repeatedly with netcat printing
out some UDP packets and mtr program as well.

Reproducible: Sometimes
Steps to Reproduce:
1.
2.
3.




Portage 2.0.51.22-r3 (default-linux/x86/2005.0, gcc-3.3.6, glibc-2.3.5-r2,
2.6.12-gentoo-r10 i686)
=================================================================
System uname: 2.6.12-gentoo-r10 i686 Intel(R) Pentium(R) M processor 1.50GHz
Gentoo Base System version 1.6.13
dev-lang/python:     2.3.5-r2, 2.4.2
sys-apps/sandbox:    1.2.12
sys-devel/autoconf:  2.13, 2.59-r6
sys-devel/automake:  1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r1
sys-devel/binutils:  2.15.92.0.2-r10
sys-devel/libtool:   1.5.20
virtual/os-headers:  2.6.11-r2
ACCEPT_KEYWORDS="x86"
AUTOCLEAN="yes"
CBUILD="i686-pc-linux-gnu"
CFLAGS="-O2 -mcpu=i686 -pipe"
CHOST="i686-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/kde/2/share/config /usr/kde/3.4/env
/usr/kde/3.4/share/config /usr/kde/3.4/shutdown /usr/kde/3/share/config
/usr/lib/X11/xkb /usr/lib/mozilla/defaults/pref /usr/share/config
/usr/share/texmf/dvipdfm/config/ /usr/share/texmf/dvips/config/
/usr/share/texmf/tex/generic/config/ /usr/share/texmf/tex/platex/config/
/usr/share/texmf/xdvi/ /var/qmail/control"
CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d"
CXXFLAGS=""
DISTDIR="/usr/portage/distfiles"
FEATURES="autoconfig distlocks sandbox sfperms strict"
GENTOO_MIRRORS="http://distfiles.gentoo.org
http://distro.ibiblio.org/pub/Linux/distributions/gentoo"
LC_ALL="en_US.UTF-8"
MAKEOPTS="-j2"
PKGDIR="/usr/portage/packages"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
SYNC="rsync://rsync.gentoo.org/gentoo-portage"
USE="x86 X aac aalib alsa apm arts audiofile avi berkdb bitmap-fonts bzip2 cdr
crypt cups curl dga divx4linux dri dv dvd dvdread eds emboss encode esd ethereal
exif expat fam ffmpeg fftw flac flash foomatic foomaticdb fortran ftp gd gdbm
gif glut gnome gpm gstreamer gtk gtk2 guile icq idn imagemagick imap imlib ipv6
jabber jack java javascript jpeg kde lcms ldap libcaca libg++ libwww live
matroska mhash mikmod ming mmap mmx mng motif mozilla mp3 mpeg mysql nas ncurses
nls ogg oggvorbis opengl oss pam pcre pdflib perl php png python qt quicktime
readline real recode ruby samba sdl sharedmem shorten slang socks5 speex spell
sse ssl svg svga tcltk tcpd tetex theora threads tiff tls truetype
truetype-fonts type1-fonts udev unicode vorbis wifi win32codecs wmf xine
xinerama xml xml2 xmms xpm xv xvid zlib userland_GNU kernel_linux elibc_glibc"
Unset:  ASFLAGS, CTARGET, LANG, LDFLAGS, LINGUAS, PORTDIR_OVERLAY

[Comment 1 Donnie Berkholz (RETIRED) 2005-12-03 14:49:37 UTC]

Are you able to reproduce this with other terms besides xterm?

[Comment 2 Donnie Berkholz (RETIRED) 2006-04-04 15:14:29 UTC]

Same goes for reproducability using modular X. Please reopen when you answer both questions.