Bug 122934 – Modular X (server) segfaults on tun (vtun) devices

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Brian Litzinger 2006-02-15 08:31:02 UTC]

Installed modular X following the guide.  On startup I got segfaults in xdmcp code.  I recompiled without xdmcp support and then it segfaulted in access.c.

The problem seems to be related to the presence of tun devices.  If my vtun tunnels are up when I start Xorg, it crashes in a while loop which is traversing a list of network devices.  When it reaches the first tun device it segfaults on a field which contains a NULL pointer.

Portage 2.1_pre4-r1 (default-linux/amd64/2005.1, gcc-3.4.5, glibc-2.3.6-r2, 2.6.15-suspend2-r6 x86_64)
=================================================================
System uname: 2.6.15-suspend2-r6 x86_64 AMD Athlon(tm) 64 Processor 3200+
Gentoo Base System version 1.12.0_pre15
distcc 2.18.3 x86_64-pc-linux-gnu (protocols 1 and 2) (default port 3632) [enabled]
dev-lang/python:     2.3.5, 2.4.2-r1
sys-apps/sandbox:    1.2.17
sys-devel/autoconf:  2.13, 2.59-r7
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:  2.16.1-r1
sys-devel/libtool:   1.5.22
virtual/os-headers:  2.6.11-r3
ACCEPT_KEYWORDS="amd64 ~amd64"
AUTOCLEAN="yes"
CBUILD="x86_64-pc-linux-gnu"
CFLAGS="-O0 -march=athlon64 -fomit-frame-pointer -pipe"
CHOST="x86_64-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/3.5/env /usr/kde/3.5/share/config /usr/kde/3.5/shutdown /usr/kde/3/share/config /usr/lib/X11/xkb /usr/lib64/mozilla/defaults/pref /usr/share/X11/xkb /usr/share/config /var/bind /var/qmail/control"
CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d"
CXXFLAGS="-O0 -march=athlon64 -fomit-frame-pointer -pipe"
DISTDIR="/usr/portage/distfiles"
FEATURES="autoconfig buildpkg ccache distcc distlocks keeptemp keepwork noclean sandbox sfperms strict"
GENTOO_MIRRORS="http://distfiles.gentoo.org http://distro.ibiblio.org/pub/linux/distributions/gentoo"
MAKEOPTS="-j6"
PKGDIR="/usr/portage/packages"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
PORTDIR_OVERLAY="/usr/local/portage"
SYNC="rsync://rsync.gentoo.org/gentoo-portage"
USE="X aac alsa amd64 avi berkdb bitmap-fonts browserplugin crypt cups divx4linux dri dv dvb dvd dvdread eds emboss encode examples faad fame ffmpeg foomaticdb fortran gimp gnome gpm gstreamer gtk gtk2 idea imlib jpeg kde lcms lzo lzw lzw-tiff mjpeg motif mp3 mp4live mpeg mpeg2 ncurses network nls nowin nsplugin nvidia opengl oss pam pdf pdflib perl player png ppds python qt readline sdl spell ssl tcpd tiff truetype truetype-fonts type1-fonts usb userlocales v4l v4l2 wxwindows xpm xprint xv xvmc zlib elibc_glibc input_devices_keyboard input_devices_mouse input_devices_synaptics input_devices_evdev kernel_linux userland_GNU video_cards_nvidia video_cards_vesa"
Unset:  ASFLAGS, CTARGET, EMERGE_DEFAULT_OPTS, LANG, LC_ALL, LDFLAGS, LINGUAS

[Comment 1 Donnie Berkholz (RETIRED) 2006-02-15 12:00:15 UTC]

This should be fixed in upstream CVS, and they're planning a new release by the end of the week.

[Comment 2 Forester 2006-03-10 22:17:11 UTC]

(In reply to comment #1)
> This should be fixed in upstream CVS, and they're planning a new release by the
> end of the week.
> 

Query?

Would this be the same bug that's causing X to seg fault before getting anywhere if not called with "-nolisten tcp" as discussed here ... http://forums.gentoo.org/viewtopic-t-420469-highlight-x+nolisten.html

A stacktrack seemed to show it was occuring inside AccessUsingXdmcp() and given the description above it sounds like it could well be the same section of code.

[Comment 3 Donnie Berkholz (RETIRED) 2006-03-10 22:53:41 UTC]

(In reply to comment #2)
> Would this be the same bug that's causing X to seg fault before getting
> anywhere if not called with "-nolisten tcp" as discussed here ...
> http://forums.gentoo.org/viewtopic-t-420469-highlight-x+nolisten.html

Likely. And not sure when the release will happen, things got delayed a bit.

[Comment 4 Donnie Berkholz (RETIRED) 2006-03-23 00:00:07 UTC]

This should be fixed in xorg-server 1.0.2.