[Mach-devel] mach 0.4.8 fc1 on fc4 problem

[David Eisenstein]

On Thu, 15 Dec 2005, John Dalbec wrote:

> I'm trying to set up a Fedora Core 1 build root in mach on Fedora Core
> 3.  The setup fails because ld-linux.so.2 -> ld-2.3.2.so segfaults in
> dl_main().  See below for details.  Any thoughts on how I can further
> diagnose the problem?
> Thanks,
> John Dalbec
> <<snip>>

Hi John,

Have you done this, from the mach README?

     "If you're on Fedora Core 2, and want to build for older targets,
     MAKE SURE you turn off vdso's by doing

     sysctl -w kernel.vdso=0

     before using mach.
     You can add an entry to /etc/sysctl.conf to make this more permanent."

I assume that will also be needed if you're running mach from FC3 or FC4
and trying to build for older targets.  Also, do you have SELinux stuff
turned on or off in your FC3 host?

Dag Wieers indicates that there can be a number of compatibility problems
that occur among versions of Red Hat and Fedora Core, and talks of a
number of things one can try when using older software on newer kernels in
his page, "Red Hat and Fedora Core Compatibility Tweaks."

It says there, "How do I know it breaks because of [new and improved
technologies integrated into their kernel]?

"In most of the cases you won't. The resulting behaviour could be a 
segmentation fault on start-up, random crashes or even unexpected 
behaviours and spurious messages. ..."

You may want to give some of Dag's tweaks a try if the vdso tweak doesn't
help you:   <http://dag.wieers.com/howto/compatibility/>.

	-David