Public bug reported:
This is in 11.10, but also occurred in 10.10
With nvidia-current (280.x) installed:
If there is no xorg.conf, everything is fine. It takes Xorg longer to
start up, because it has to load extra drivers (before unloading all but
the nvidia driver), but the problem being reported does not occur.
But if one creates an xorg.conf (whether with nvidia-xconfig or nvidia-
settings, or just by hand), there is a severe stability problem.
Immediately upon starting emacs, the Xorg started using that xorg.conf
dies with a segmentation fault, causing an abrupt logout.
This is not limited to emacs. The same thing happens when starting
VirtualBox. Presumably other programs can trigger the SEGV.
To reproduce the problem, you just need to be running an Xorg that was
started using an xorg.conf that loads the nvidia-current driver(or a
related one from the nvidia-260 to nvidia-290 family) and type "emacs"
from a bash prompt.
As stated above, the problem only occurs when there is an xorg.conf
file. If the same driver is instead loaded via Xorg's heuristics
because there was no xorg.conf, then Xorg does not incur the SEGV when
emacs starts.
The problem does not appear to occur with the legacy "nvidia-96" driver
still supplied for old GPU's. I do not know whether it occurs with the
legacy nvidia-173 driver. I've reproduced it with every incarnation of
nvidia-current since nvidia-260.
If one had to guess, something used by nvidia-current is accidentally
uninitialized, but when there is no xorg.conf, xorg loads many other
drivers (and then unloads all but "the best choice" during startup)
and one of those other drivers happens to initialize that "something".
apt-cache policy nvidia-current
nvidia-current:
Installed: 280.13-0ubuntu6
Candidate: 280.13-0ubuntu6
Version table:
*** 280.13-0ubuntu6 0
500 http://archive.ubuntu.com/ubuntu/ oneiric/restricted i386 Packages
100 /
-----------------------------------------------------------------------------------------------------------------------
The attachment contains an xorg.conf created by nvidia-settings. When that
(or ANY!) conf was in use, emacs triggered a segmentation violation, as shown
in the file "Xorg.0.log-SEGV".
Looking at the file: Xorg.0.log, note that without being told what to
do by an xorg.conf, Xorg loaded, in sequence, the six modules:
[ 6529.541] (II) LoadModule: "nvidia"
[ 6529.541] (II) LoadModule: "nouveau"
[ 6529.542] (II) LoadModule: "nv"
[ 6529.542] (II) LoadModule: "vesa"
[ 6529.543] (II) LoadModule: "fbdev"
[ 6529.545] (II) LoadModule: "fbdevhw"
and then unloaded in sequence the five modules
[ 6529.541] (II) LoadModule: "nouveau"
[ 6529.542] (II) LoadModule: "nv"
[ 6529.542] (II) LoadModule: "vesa"
[ 6529.543] (II) LoadModule: "fbdev"
[ 6529.545] (II) LoadModule: "fbdevhw"
So that the only one of the original six that remained was "nvidia".
It seems a reasonable hypothesis that one of the other five modules
performed an initialization that "nvidia" should have performed, but did
not, and without that initialization having taken place in the
instance of Xorg which had an xorg.conf, when emacs exercised a code
path which involved the uninitialized item, the SEGV ensued.
** Affects: nvidia-graphics-drivers (Ubuntu)
Importance: Undecided
Status: New
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/930350
Title:
xorg.conf plus emacs causes abrupt logout via Xorg SEGV
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers/+bug/930350/+subscriptions
--
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
