Re: m4 illegal instruction

[Eric Blake]

On 07/28/2014 11:39 PM, Alan Seiden wrote:
> Dear M4 team:
> 
> With m4-1.4.17-1, when I do:
> m4 --version
> or anything else, I get an error such as:
> 
>  /usr/bin/m4: internal error detected; please report this bug to
> <address@hidden>: Illegal instruction

Thanks for the report.  Is this a version of m4 you built yourself, or
that you downloaded pre-compiled?  The trailing -1 in the version string
you mentioned makes it sound like a pre-compiled binary.  Are you sure
it is the right binary for your architecture?  Does 'file m4' give you
any insight?  If it is pre-compiled, you will be better off getting help
from the person that provided you the pre-built binary.

If it is self-compiled, can you run a debugger on the binary to see at
what step it crashes?  Can you get a backtrace at the time of the
signal?  The fact that it is displaying a message from m4 means that
main() is getting executed at least to the point of installing a SIGILL
handler.  I suspect that the problem is occurring during the call to
c_stack_action() inside main(), since that occurs before option parsing
and you are seeing the behavior even for an attempt to do --version.  Is
your build of m4 using libsigsegv or not?  If you are using libsigsegv,
does that library pass self-tests on your platform?  If you are not
using libsigsegv, I'm suspecting that something in the gnulib code for
setting up a stack overflow handler is triggering a SIGILL.  Either way,
it would be nice to port that code to work for your setup.

> 
> I'm running this on AIX (IBM i).

I don't have access to this type of machine, so I suspect the bulk of
the debug effort will be on your shoulders.  Good luck.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

signature.asc
Description: OpenPGP digital signature