[PlanetCCRMA] omlinux: line 41; 3980 Segmentation fault...

Wes Shull wes@kuoi.asui.uidaho.edu
Wed Mar 24 19:02:02 2004

On Wednesday 24 March 2004 18:26, Fernando Pablo Lopez-Lezcano wrote:
> I'll be darned! It seems to work. Sometimes. 
> :-)
> Not very consistent, which is surprising. It segfaults randomly at
> startup.

Hmm, that reminds me of something else.  Prelink and the loader use random 
virtual memory slot assignment by default in FC2, in FC1 too IIRC.  This 
means that any object that needs to load at a specified address may fail 
to load sometimes, if something else has been randomly mapped into the 
address it needs for that particular load.  (This is in particular a 
problem trying to get mplayer to use win32 codecs.)  This sounds like it 
could be the same problem here...

I'm not entirely clear on how these settings all interact, so I don't know 
in what order you should try these, but the relevant settings are:

echo 0 > /proc/sys/kernel/exec-shield-randomize
(also optionally put "kernel.exec-shield-randomize = 0" in /etc/sysctl.conf 
so the setting persists across reboots)

echo 0 > /proc/sys/kernel/exec-shield
(also optionally put "kernel.exec-shield = 0" in /etc/sysctl.conf so the 
setting persists across reboots)

remove the -R and/or -m from PRELINK_OPTS in /etc/sysconfig/prelink, or 
even set it to --no-exec-shield (see manpage for prelink for all options), 
then rerun prelink (touch /var/lib/misc/prelink.force then 
run /etc/cron.daily/prelink; this will take a long time)

You could even disable prelinking and then un-prelink everything, but I 
don't think the basic prelink operation is the problem; it's just a 

Actually I have my prelink set to --no-exec-shield right now; I'll see if I 
can get the relevant packages to work on my FC2 system.

I can only imagine what kind of fun we're going to have with selinux...